Other ORAS OU Viability Ranking Thread V2 - Check Post #2500 PG. 100

[firehusky]

No way is mega medicham as good as mega gallade or better. That's exaggerating it way too much. Mega gallade actually has respectable bulk, while mega medicham is pretty frail. Also it's not that weak, so it doesn't always need a boost to put a dent into something. CC is also much more reliable than hjk, and the difference in power doesn't even make a huge difference. Justified is also kinda cool to nab a free attack boost by coming in on a dark-type attack. Skill swap is gimmicky to say the least, but it still is a rather cool option to beat mega sableye. (Foresight from mega medicham gets bounced back by magic bounce, I believe.) To be honest, they're not even that similar bar their shared psychic / fighting typing. Mega medicham is more of the power > speed and is a nuke / wallbreaker hit and run attacker. Mega gallade runs SD, making it stronger in the long run, and more of a set up sweeper, while also having access to knock off, something that mega medicham would kill for. Running thunder punch or ice punch isn't really the best option atm. I feel like the best set is fake out / bullet punch / hjk / zen headbutt, so it actually doesn't really have all that room for coverage, and bulky psychic types are all handled decently by bisharp. You also can't really say that mega medicham dismantles defensive cores much better than mega gallade, as both are walled by mega sableye, which is extremely common on defensive teams. However, mega medicham is probably better at dismantling bulkier and balanced builds, such as rotom-w + heatran + ferrothorn, and clefable + heatran. Mega gallade is definitely better against offense however, thanks to it's much better speed tier of 110.
I think people are jumping on the hype train way too fast, mega medicham is definitely good, and mega gallade was really overhyped, but mega medicham isn't better than mega gallade. Heck, they hardly do the same things.

 

[Wargreymon]

The meta is very favorable towards things with immediate hit-and-run power right now, like Banded Victini and Lando-I, both because set-up opportunities have seemingly become harder to come by and profit from and that the meta is quite bulky. Medicham does of course face competition in the wall-breaking role, but it's pretty damn good at it and is under prepared for now. Deserves a raise.

I just want to point out that I think you're really underselling Mega Gallade's power without any boosts. Mega Gallade is very capable of the hit and run style you speak of because close combat is a total nuke. It's extremely hard to find non resists that aren't dismantled by it. The extra speed that Gallade has over Medicham also aids in hit and run during crucial situations. I guess Gallade only really has close combat because zen and knock off aren't hitting anywhere near as hard as Medicham's zen/coverage, but Gallade is still extremely powerful and capable of hit and run with close combat alone.
I know it's a physical move (therefore susceptible to burns and intimidate) and fighting is worse offensively than fairy, but to put it in perspective, in terms of raw power it actually hits harder than Gardevoir's hyper voice. Here's a pretty ridiculous calc;

252 Atk Mega Gallade Close Combat vs. 0 HP / 0 Def Latias: 128-151 (42.5 - 50.1%) -- 91.8% chance to 2HKO after Stealth Rock

Even the bulky defog variant has basically a 50% chance to get 2HKO'd. So yeah, Mega Gallade definitely has immediate power.

Edit: Kind of Greninja'd by firehusky

 

[jbtc10]

No way is mega medicham as good as mega gallade or better. That's exaggerating it way too much. To be honest, they're not even that similar bar their shared psychic / fighting typing. Mega medicham is more of the power > speed and is a nuke / wallbreaker hit and run attacker. Mega gallade runs SD, making it stronger in the long run, and more of a set up sweeper, while also having access to knock off, something that mega medicham would kill for. Running thunder punch or ice punch isn't really the best option atm. I feel like the best set is fake out / bullet punch / hjk / zen headbutt, so it actually doesn't really have all that room for coverage, and bulky psychic types are all handled decently by bisharp. You also can't really say that mega medicham dismantles defensive cores much better than mega gallade, as both are walled by mega sableye, which is extremely common on defensive teams. However, mega medicham is probably better at dismantling bulkier and balanced builds, such as rotom-w + heatran + ferrothorn, and clefable + heatran. Mega gallade is definitely better against offense however, thanks to it's much better speed tier of 110.
I think people are jumping on the hype train way too fast, mega medicham is definitely good, and mega gallade was really overhyped, but mega medicham isn't better than mega gallade. Heck, they hardly do the same things.

They are indeed very different, but Gallade struggles against both balance and stall, because things like Clefable (Unaware) and Talonflame are so common on Balance and Sableye on stall. Medicham struggles against HO (although the double prio set can be ok against it), but can at least rip through balance teams, and only really falls flat against pure stall due to Sableye. Basically, it's exactly what you said; they're not even that similar, and one of the reasons Medicham was dropped at the start of ORAS was "lol, totally outclassed by Gallade" which we now know to be wrong and not even the most valid comparison to begin with. To summarize, Medicham is better than what it has been made out be, and Gallade isn't quite as good as what it was made out to be, hence why I was saying that they are quite on par in terms of how effective they can be depending on your team requirements, as well as how they objectively fit in the meta.

 

[Clone]

Gallade doesn't struggle against balance. Common fat cores like FerroTran and ferro / Slowbro / Gliscor lost to Gallade because Gallade nukes them with a +2 CC. Yall are really underselling gallades power. A base 120 power move coming off of a Base 165 Attack is by no means underwhelming lol. To put it in perspective, mixed defense hippo (252 / 144+) has a small chance of being 2HKOed after rocks and a layer of spikes, and hippo is one of the sturdiest walls in the tier (+ getting that extra 10% isn't too hard when you apply offensive pressure to it). Add on a potential SD, and you have a crazy good wallbreaker that excels against balance; it doesn't struggle against it. I personally don't agree with it dropping but I'm not gonna waste my time arguing about it.

As for Medicham, it's fine where it is. The only thing it has going for it over Gallade is more immediate power, and in return it's speed tier is much worse, it's walled by every fat psychic type in the tier, and it has horrendous bulk that gives it zero switch in opportunities. Dual priority is really being overhyped because fake out is a one turn move and BP is weak as shit against anything it hits neutrally. It has its uses, sure, but it's not saving Medicham from a faster anything bar a weakened diancie. It also means Cham loses what little coverage it has, namely t punch for Slowbro. The only playstyle that Cham matches up against better than Gallade is stall, but thats really it. Gallade has a better matchup bs most balance and all offense teams than Cham does. C+ is perfect for it. It's a good mon in its own right and certainly viable, but 9 times out of ten Gallade is better.

 

[Vert]

to d rank
alright, so you guys might be thinking this isn't viable so i am preparing myself for a shitstorm. mantine has a nice niche on select teams and is so much better than other pokemon in d rank such as cofagrigus, salamence, etc. at its niche.

a. mantine checks 3 threats that rose rapidly in usage in the past months: keldeo, landorus-i, and zardy. the first two s rank 'mons are dominating forces and beats them if keldeo (air slash + haze remember) lacks hidden power electric (rare) and if landorus-i lacks rock slide (rare though rising in usage). mantine can use these opportunities to use defog, spread a burn with scald, or support the team with tailwind or toxic something incoming. these moves are only there if you an additional way to check subcm keldeo. haze actually prevents suicune from setting up, allowing you to bring in a powerful special attacker to dismantle it after such as life orb gengar or mega alakazam. mega slowbro is another threatening 'mon and haze ends any attempts to sweep. it also checks volcarona which is rising in usage too.

b. mantine's ability to use defog on top of these traits is the main reason on how this fits on select teams. teambuilding is very pressurized at the moment, so these combined give it a place on select teams. also, it can remove hazards while beating heatran which is exclusive to starmie and salamence (lel). speedy excadrill is more offensively inclined, so it doesn't compare to mantine's defensive niche.

c. its access to water absorb is amazing currently considering how balance builds are everywhere and how scald happy the metagame is. this allows it to take advantage of current trends and prevent it from being worn down too easily. mantine's great synergy with other walls such as heatran, ferrothorn, and hippowdon also allows it to fit in and take advantage of the situation. a huge perk about mantine is that its a keldeo check that can't be burned by scald because it is immune to it, smething that screws up amoonguss, mega venusaur, latias, and other things like rotom-w for example.

d. mantine's movepool is adjustable to your teams needs, so it isn't one dimensional at times. if mantine is your only keldeo check, you can run air slash, but if you have unaware clefable for example, you can fit in toxic to help with stallbreaking. on more balanced builds, tailwind is an option as well to make wallbreakers such a mega heracross, gengar, and mega gardevoir in to speedy end game machines. mirror coat is a great move that can kill mega gardevoir, mega altaria, mega alakazam, latios, and other special attacker if it is timed correctly.

all these factors honestly warrant mantine usage as it diid in late xy before getting removed. it is a cool special wall and should be added :]

 

[Scotti]

I agree with vertex that mantine should be d rank.

Mantine is a mon from the gods. Mantine was the first water pokemon to be made. With it amazing powers it was able to create lakes, seas, and even vast oceans. After it created all of that, it wanted water to come from the sky to. So mantine went and created its sidekick Kyogre. Kyogre made it rain everyday and all day, but mantine rival camerupt hated mantine. So camerupt the first land pokemon created groudon. Groudon was used to make it sunny all the time. In the end kyogre and groudon and mantine and camerupt fought, and they all got beat up and went back to where they came. And that is how mantine became unranked :3

Mantine has great special bulk and typing allowing it to take on charizard y, volc, keldeo, and other special mons. This combine with the move scald, allows mantine to become a great mon on stallier teams. Mah boi yuttt used mantine back in the day, and he put in work. In the end make lord mantine d rank.

EDIT: It also has defog seperating it from other water types and spdef gyarados.

 

[MegaMogwai]

I'm just going to say that Mega Abomasnow is much more viable than what it seems to be on paper. Yes SR weakness, yes horrible speed. But it's bulk enables it to take hits really well and the Ice/Grass STAB combination is very hard to switch into.

I got my reqs for the Mega Metagross suspect using only my bulky offense team built around Mega Abomasnow (with a trick room support from Mew). 53 wins and 21 losses. Not trying to show off or anything because there's nothing to show off from getting reqs, my point is that I obtained them with a team built around a mon many of you refuse to include in the D ranking. I say that with proper support (which believe me, it needs a lot of) Mega Abomasnow is most certainly viable.

But that's just my humble opinion and to be honest if he stays unranked, I don't really mind at all, not like it affects me haha. Just wanted to share my opinion, seeing as someone tagged me in a post talking about it here.

 

[Dark G]

yeah sorry, I know I misread and thought you said 3 attacks + taunt gatr, lol.
A solid wallbreaker is vital for using hawlucha, but it requires lots of team support. Other late game set up sweepers such as BD azu don't require that much support, while also being able to do stuff besides belly drum. Obviously if your opponent's only answer to hawlucha is lando-t, he won't let it get weakened. The fact that lando-t could get weakened by the lategame doesn't change the fact that it can still check hawlucha. That's like saying in practice heatran isn't a zard x counter because it's used to check many pokemon such as talonflame and latios, so it'll get worn down to the point that +1 zard x can break past it. Being able to set up on gliscor, lando-t + non hp ice lando-i, sableye and non whirlwind hippowdon also isn't really that special considering other pokemon such as SD gliscor can also do it.

lol yeah I figured you misread my post...just had to make sure

Hawlucha doesn't need that much support granted the matchup is either even or is in its favour, saying "lots" was a bit of a stretch. BD Azu doesn't share the same set-up fodder with Hawlucha so that argument isn't valid when we consider teambuilding and how we build around certain mons. Lucha and BD Azu are two late-game sweepers that work completely different.

Again, Lando-T isn't a solid check to Lucha at all.

I'll admit my logic was somewhat flawed but the point I was trying to make was that providing calcs to utility mons that are used to check multiple offensive threats is silly because they are based on ideal scenarios. It won't work that way in practice.

 

[Sochlo]

It's ironic that Medicham is being discussed for a raise right after Gallade dropped (it shouldn't have dropped imo but w/e I shared my opinion on that already) because the things holding Gallade back also hinders Medi, namely the ass defensive typing not letting it switch in and being revenge killed a lot, only with Medi you have less defenses AND less speed further compounding those flaws (lol bullet punch).

On to Medicham itself it's always been a good Pokemon even after ORAS, it's still a scary as fuck wallbreaker that nothing wants to switch into. I was against its placement in C+ back when ORAS started thinking it was just a kneejerk reaction but looking at the ranks now I think C+ is where it should be, it's better than most of the mons in its rank but I can't honestly see it being a rank above things like Jesus Bird, Cobalion, and Tyrantrum (which is also a scary as fuck wallbreaker nothing wants to switch into but with a way to boost speed). I don't think people suddenly realizing after months that Medicham is still pretty decent is enough of a reason to raise it to B-.

 

[Dark G]

Agreeing with the consensus in keeping M-Medicham in C+. M-Sableye is just far too common on balance and especially stall in the current meta for it to wallbreak efficiently. Atleast M-Gallade has a chance of beating it 1V1 wih its Sub,SD,CC, Knock off set; M-Medicham just gets straight up owned. The one playstyle (stall) that it arguably outclassed M-Gallade in is almost irrelevant due to M-Sableye being on every ORAS stall team.

I'd really only use M-Medicham over M-Gallade as a sure check to M-Diancie or if my team was desperate for any form of priority. The immediate power it has over M-Gallade isn't too appealing to me since M-Gallade hits hard enough as it is with STAB CC. It's not completely inferior and does have certain niches to boast over M-Gallade but for the most part M-Gallade just flat out does the job better in most matchups. Keep it at C+

 

[DarkNostalgia]

Quite a few people have mentioned this already, but I would like to nominate Weavile to B+ once again.
With the rise of new threats such as Mega Altaria, both forms of Landorus, Mega Metagross, Garchomp, Gliscor, Weavile stands out as a great check to all of the former. Ice is, I dare say, one of the best offensive typings in the game right now, considering things like Garchomp, Gliscor, Altaria and Landorus-T and -I are quite commonplace. Access to Ice Shard really does make Weavile a threat, albeit underrated, allowing it to revenge kill Rock Polish Landorus-Incarnate as well as weakened Dragon Dance Mega Altaria, extremely big threats in the meta right now. Not to mention it has Knock Off, a great utility move in general that can cripple Weavile's usual switch-ins, such as Keldeo and Azumarill, allowing for easy switches, doubling and predictions in general. In addition, Weavile has access to numerous coverage move and/or utility moves, such as Poison Jab, Pursuit, Taunt, Swords Dance, Low Kick and Aerial Ace, allowing Weavile to get past it's usual checks with various lures; for example, Poison Jab and Aerial Ace both 2HKO Azumarill and Keldeo, respectively.
A blazingly fast Speed tier of 125 really does put Weavile over the top, letting it outspeed threats such as Tornadus-Therian and Latios. It is definitely comparable to Mamoswine, and is only fitting that Weavile should be one subrank lower than Mamoswine only, as it can do things that Mamoswine cannot do, such as revenge kill weakened Mega Metagross, which is pretty huge in a meta which is defined by it, as well as having more Speed to be able to use Icicle Crash to eliminate things that Mamoswine cannot get rid of with Ice Shard, such as Latios.
I don't have replays, sadly, but I do have some relevant calcs:

Calcs

S Rank:

252 Atk Life Orb Weavile Knock Off vs. 0 HP / 0 Def Mega Metagross: 187-221 (62.1 - 73.4%) -- guaranteed 2HKO
252 Atk Life Orb Weavile Ice Shard vs. 0 HP / 0 Def Landorus: 348-421 (109 - 131.9%) -- guaranteed OHKO
252 Atk Life Orb Weavile Icicle Crash vs. 64 HP / 0 Def Mega Altaria: 315-374 (102.6 - 121.8%) -- guaranteed OHKO
252 Atk Life Orb Weavile Ice Shard vs. 64 HP / 0 Def Mega Altaria: 151-179 (49.1 - 58.3%) -- 98.4% chance to 2HKO
252 Atk Life Orb Weavile Knock Off (97.5 BP) vs. 0 HP / 0 Def Keldeo: 105-125 (32.5 - 38.6%) -- 99.1% chance to 3HKO

A Rank:

Out of A rank, only Azumarill, Clefable, Lopunny, Sableye and possibly Talonflame win against Weavile. However, Azumarill loses to the rarer Poison Jab, as does Clefable, and Talonflame under 40% health are KOed by Ice Shard. Furthermore, Mega Charizard X is actually 2HKOed by Icicle Crash 90% of the time, even without Stealth Rocks up.

252 Atk Life Orb Weavile Icicle Crash vs. 104 HP / 0 Def Mega Charizard X: 156-185 (48.2 - 57.2%) -- 90.6% chance to 2HKO
252 Atk Life Orb Weavile Icicle Crash vs. 252 HP / 172 Def Clefable: 179-212 (45.4 - 53.8%) -- 2% chance to 2HKO after Leftovers recovery
252 Atk Life Orb Weavile Ice Shard vs. 88 HP / 0 Def Talonflame: 107-126 (33.5 - 39.4%) -- guaranteed 3HKO (Talonflame is slower, since they mostly run 168 Jolly)

 

[Eraxxer]

Quite a few people have mentioned this already, but I would like to nominate Weavile to B+ once again.
With the rise of new threats such as Mega Altaria, both forms of Landorus, Mega Metagross, Garchomp, Gliscor, Weavile stands out as a great check to all of the former. Ice is, I dare say, one of the best offensive typings in the game right now, considering things like Garchomp, Gliscor, Altaria and Landorus-T and -I are quite commonplace. Access to Ice Shard really does make Weavile a threat, albeit underrated, allowing it to revenge kill Rock Polish Landorus-Incarnate as well as weakened Dragon Dance Mega Altaria, extremely big threats in the meta right now. Not to mention it has Knock Off, a great utility move in general that can cripple Weavile's usual switch-ins, such as Keldeo and Azumarill, allowing for easy switches, doubling and predictions in general. In addition, Weavile has access to numerous coverage move and/or utility moves, such as Poison Jab, Pursuit, Taunt, Swords Dance, Low Kick and Aerial Ace, allowing Weavile to get past it's usual checks with various lures; for example, Poison Jab and Aerial Ace both 2HKO Azumarill and Keldeo, respectively.
A blazingly fast Speed tier of 125 really does put Weavile over the top, letting it outspeed threats such as Tornadus-Therian and Latios. It is definitely comparable to Mamoswine, and is only fitting that Weavile should be one subrank lower than Mamoswine only, as it can do things that Mamoswine cannot do, such as revenge kill weakened Mega Metagross, which is pretty huge in a meta which is defined by it, as well as having more Speed to be able to use Icicle Crash to eliminate things that Mamoswine cannot get rid of with Ice Shard, such as Latios.
I don't have replays, sadly, but I do have some relevant calcs:

Calcs

S Rank:

252 Atk Life Orb Weavile Knock Off vs. 0 HP / 0 Def Mega Metagross: 187-221 (62.1 - 73.4%) -- guaranteed 2HKO
252 Atk Life Orb Weavile Ice Shard vs. 0 HP / 0 Def Landorus: 348-421 (109 - 131.9%) -- guaranteed OHKO
252 Atk Life Orb Weavile Icicle Crash vs. 64 HP / 0 Def Mega Altaria: 315-374 (102.6 - 121.8%) -- guaranteed OHKO
252 Atk Life Orb Weavile Ice Shard vs. 64 HP / 0 Def Mega Altaria: 151-179 (49.1 - 58.3%) -- 98.4% chance to 2HKO
252 Atk Life Orb Weavile Knock Off (97.5 BP) vs. 0 HP / 0 Def Keldeo: 105-125 (32.5 - 38.6%) -- 99.1% chance to 3HKO

A Rank:

Out of A rank, only Azumarill, Clefable, Lopunny, Sableye and possibly Talonflame win against Weavile. However, Azumarill loses to the rarer Poison Jab, as does Clefable, and Talonflame under 40% health are KOed by Ice Shard. Furthermore, Mega Charizard X is actually 2HKOed by Icicle Crash 90% of the time, even without Stealth Rocks up.

252 Atk Life Orb Weavile Icicle Crash vs. 104 HP / 0 Def Mega Charizard X: 156-185 (48.2 - 57.2%) -- 90.6% chance to 2HKO
252 Atk Life Orb Weavile Icicle Crash vs. 252 HP / 172 Def Clefable: 179-212 (45.4 - 53.8%) -- 2% chance to 2HKO after Leftovers recovery
252 Atk Life Orb Weavile Ice Shard vs. 88 HP / 0 Def Talonflame: 107-126 (33.5 - 39.4%) -- guaranteed 3HKO (Talonflame is slower, since they mostly run 168 Jolly)

Definitely agree. Ice is just becoming amazing in this meta, more amazing than before now that Landorus-I has replaced Landorus-T in S Rank and a 4x effective Ice moves can actually OHKOs for once. Ice becoming more viable is in a very similar vein to Mega Abomasnow, which is why I'm arguing for it to be D rank. 125 Speed tier isn't really what it used to be, with Mega Lopunny shitting on it, and poor bulk combined with weakness to Stealth Rocks is hindering, but nothing really switches in on this monster barring very select walls, many of which can't really do much to it, and Keldeo/Azu/others, which as you said are smacked by coverage moves.

I'm just going to say that Mega Abomasnow is much more viable than what it seems to be on paper. Yes SR weakness, yes horrible speed. But it's bulk enables it to take hits really well and the Ice/Grass STAB combination is very hard to switch into.

I got my reqs for the Mega Metagross suspect using only my bulky offense team built around Mega Abomasnow (with a trick room support from Mew). 53 wins and 21 losses. Not trying to show off or anything because there's nothing to show off from getting reqs, my point is that I obtained them with a team built around a mon many of you refuse to include in the D ranking. I say that with proper support (which believe me, it needs a lot of) Mega Abomasnow is most certainly viable.

But that's just my humble opinion and to be honest if he stays unranked, I don't really mind at all, not like it affects me haha. Just wanted to share my opinion, seeing as someone tagged me in a post talking about it here.

Didn't say what's up internet :[ . But getting reqs isn't a walk in the park, it can be difficult sometimes and getting reqs with a team around Mega Abomasnow shows that either it's definitely viable in OU, or you're a god, and I'm subscribed, you're a really really good battler (:D) but noone is perfect (D:). 53 and 21 really says something.

 

[Halcyon.]

I think the extra speed, and a much better STAB that you can spam that lets you go at +2 is more useful, Earth Power is useful for Heatran, but Serperior has a


The thing is that you can also kill Megagross on incoming with Serperior, and unlike Shaymin it does not rely on luck, and even after killing Megagross you still have a good momentum because you are at +2 mininum, and that is in the case Megagross stays, the difference between Serperior is that even in Megagross leaves you still are at a +2, and is more difficult to come into a Serperior because the ability to outrun base 110.



Serperior also has Knock Off, something that also shaymin would kill for(not necessarily but we know how good is to cripple a Raikou or an Scarf mon on incoming), Eart power is cool and useful, but aside from Heatran what Shaymin is handling better than Serperior in practice, or supporting the team like Celebi?

Rest is giving an opponent a free turn, and if they predict you it becomes bad, that is why Rest is kind of difficult to use as a reliable recovery, and synthesis is kinda reliant on weather, and rain and sand are somewhat common now.

I mean handling just a mon better(Heatran) at the cost of having much less offensive presence and relying on luck is not enough for me.

Shaymin is kinda too easy to switch in, and if your luck based move does not trigger even more.

You're greatly underestimating the advantages Shaymin has over Serperior. Shaymin has more initial power. SIGNIFICANTLY more initial power. Modest Nature and 25 Base SAtk more than Serperior is a huge difference in power. We're talking like 20% difference. And you also have a 40% of having virtually the same effect that Serperior's Contrary gives it. Add onto that it's vastly superior bulk and ability to hit both Heatran and Ferrothorn for OHKOs after Rocks, and that should be reason enough for some teams to choose Shaymin. Is it as good as Serperior? Hell no. 113 Speed and a guaranteed +2 is amazing. That's why Serperior is B rank. But like it or not Shaymin does have noticeable advantages over Serperior, and those differences make it viable.

Also some of your points don't make any sense lol. Knock Off? Serperior almost never runs it but alright. Rest gives a free turn? Uh then don't run it, run Giga Drain or Synthesis like Serperior. It's easy to switch into? I mean Latios and Latias can switch in, but they're easy to trap so that's not that big a deal. AV Raikou? Not going to take a Seed Flare + SDef drop too well, and it can't do anything back. Torn-T can switch in, but it switches into Serperior too.

Like seriously just try Shaymin. I honestly don't think you have. Try it and then tell me that it's not at least worthy of D. But I really do think it fits better in C- or C.

 

[pika pal]

If Shaymin is going to be ranked, Seed Flare's perks NEED to be acknowledged in context of this metagame. Seed Flare has a 40% chance to cut Sp. Def in half. One of the things I remember seeing brought up for Keldeo (who's in S-Rank) is that Burn lets it muscle past its own checks. I am not comparing Shaymin to Keldeo in terms of effectiveness (even if I think Pony should be A+), but if a 30% chance to wear down a check/counter is a perk for Keldeo, a 40% chance to turn counters to checks or just outright beat a check has to be acknowledged for Shaymin. What makes this such a boon to Shaymin is that Keldeo, while his checks can be worn down, still can't always beat them immediately, so he's forced out and losing momentum, while Shaymin can come out on top with those boosts against what was supposed to force it to leave.

One immediately concerning mon for Shaymin would be the Latis. However, 40% of the time, Latios suffers a drop that turns Seed Flare into a 2HKO after SR or LO recoil.
252 SpA Life Orb Shaymin Seed Flare vs. 0 HP / 4 SpD Latios: 97-116 (32.4 - 38.7%) -- 98.6% chance to 3HKO
252 SpA Life Orb Shaymin Seed Flare vs. -2 0 HP / 4 SpD Latios: 195-230 (65.2 - 76.9%) -- guaranteed 2HKO

Access to Earth Power also means Shaymin's not nearly as hard pressed to deal with Steels or suffering coverage options overall as Serperior can be prone to. Lacking a dark weakness actually means that Shaymin is not only able to escape Pursuit trappers, but outright beat them if it enters on a double switch.
252 SpA Life Orb Shaymin Seed Flare vs. 0 HP / 0 SpD Tyranitar in Sand: 283-338 (82.9 - 99.1%) -- guaranteed 2HKO
252 SpA Life Orb Shaymin Earth Power vs. 0 HP / 52 SpD Bisharp: 265-315 (97.7 - 116.2%) -- 87.5% chance to OHKO

Celebi would be another comparison, given the shared stats, separated by different typing and movepool. Celebi will almost always want Baton Pass not just for support, but because it needs to escape Pursuit. Celebi's Giga Drain is much weaker than Shaymin's Seed Flare, so Celebi usually can't risk itself vs Trappers
252 Atk Tyranitar Crunch vs. 0 HP / 0 Def Celebi: 270-318 (79.1 - 93.2%) -- guaranteed 2HKO after sandstorm damage
252 SpA Life Orb Celebi Giga Drain vs. 0 HP / 0 SpD Tyranitar in Sand: 179-213 (52.4 - 62.4%) -- guaranteed 2HKO

Seed Flare is the thing that makes Shaymin such a potent Wallbreaker, already plenty powerful in its own right, backed by Shaymin's Sp. Attack stat (Higher than Serp's at least) can also drop the opponent's Defense in a manner similar to Leaf Storm. However, since Shaymin drops the opponent instead of beating itself, the opposing Pokemon isn't in the clear just because it was forced out. For example, say Ferrothorn is dropped switching in
252 SpA Life Orb Shaymin Seed Flare vs. 252 HP / 168 SpD Ferrothorn: 40-47 (11.3 - 13.3%) -- possibly the worst move ever
252 SpA Life Orb Latios Draco Meteor vs. -2 252 HP / 168 SpD Ferrothorn: 209-247 (59.3 - 70.1%) -- guaranteed 2HKO after Leftovers recovery
-2 252 SpA Life Orb Latios Draco Meteor vs. -2 252 HP / 168 SpD Ferrothorn: 105-125 (29.8 - 35.5%) -- guaranteed 4HKO after Leftovers recovery

The sum of those rolls is (100.4 - 118.9%), which means Ferrothorn without Leftovers (Rocky Helmet) or with some wear on it can be beaten by Latios without HP Fire.

I know this is probably way too specific an example to support my point well, but essentially, the drops help Shaymin cripple switch-ins trying to steal Momentum from it. I chose Ferrothorn because its survivability is a combination of both type and bulk, so reducing either really reduces what he can wall.

Supporting Shaymin to D or C's

 

[13_luckynumber]

Kingdra should drop to B
Kabutops and Omastar should drop to B-
Mega Swampert should drop to C+

All four depend heavily on rain to function. That means you have to dedicate around 2 other Pokemon on your team to support them. That opportunity cost limits team building pretty severely. And although rain is very effective when done right, the cost is still too much imo.

On why they are ranked differently:
- kingdra is can sort of function outside of rain with the critDra set and is the best rain abuser imo (B rank)
- kabutops cannot do anything without rain, still not that threatening under rain but can pull off a spin or an aqua jet even outside of it in a pinch so B- rank
- omastar also cannot do anything without rain but has great offensive presence under rain so B-
- mega swampert cost you your mega slot, waste 1 turn on your rain on the turn it mega evolves, and does not hit too much harder than kabutops. There are better megas to usecon a rain team. (C+ rank)

I can say more but I think you get my idea here: these four require lots of support to function. Drop them

 

[Invok3r]

Kingdra should drop to B
Kabutops and Omastar should drop to B-
Mega Swampert should drop to C+

All four depend heavily on rain to function. That means you have to dedicate around 2 other Pokemon on your team to support them. That opportunity cost limits team building pretty severely. And although rain is very effective when done right, the cost is still too much imo.

On why they are ranked differently:
- kingdra is can sort of function outside of rain with the critDra set and is the best rain abuser imo (B rank)
- kabutops cannot do anything without rain, still not that threatening under rain but can pull off a spin or an aqua jet even outside of it in a pinch so B- rank
- omastar also cannot do anything without rain but has great offensive presence under rain so B-
- mega swampert cost you your mega slot, waste 1 turn on your rain on the turn it mega evolves, and does not hit too much harder than kabutops. There are better megas to usecon a rain team. (C+ rank)

I can say more but I think you get my idea here: these four require lots of support to function. Drop them

"omastar also cannot do anything without rain but has great offensive presence under rain so B-"

I just wanted to point out that omastar can do things outside of rain, it has access to 3 types of hazards, and weak armor makes it a good suicide lead.

 

[Kurona]

Kingdra should drop to B
Kabutops and Omastar should drop to B-
Mega Swampert should drop to C+

All four depend heavily on rain to function. That means you have to dedicate around 2 other Pokemon on your team to support them. That opportunity cost limits team building pretty severely. And although rain is very effective when done right, the cost is still too much imo.

On why they are ranked differently:
- kingdra is can sort of function outside of rain with the critDra set and is the best rain abuser imo (B rank)
- kabutops cannot do anything without rain, still not that threatening under rain but can pull off a spin or an aqua jet even outside of it in a pinch so B- rank
- omastar also cannot do anything without rain but has great offensive presence under rain so B-
- mega swampert cost you your mega slot, waste 1 turn on your rain on the turn it mega evolves, and does not hit too much harder than kabutops. There are better megas to usecon a rain team. (C+ rank)

I can say more but I think you get my idea here: these four require lots of support to function. Drop them

They do not require a lot of support to function -- what you are failing to understand is that Rain has so many good setters and so many good abusers it is an actual playstyle, of which Dra, Kabu, Oma and - arguably controversially - Swampert are by far the best abusers.
Yes they are only viable on that one playstyle; but that's why they're nowhere above the B rankings. I get the feeling you've never gone up against or used a good rain team before; it is ridiculously destructive.

 

[13_luckynumber]

"omastar also cannot do anything without rain but has great offensive presence under rain so B-"

I just wanted to point out that omastar can do things outside of rain, it has access to 3 types of hazards, and weak armor makes it a good suicide lead.

But dont Scolipede, Skarmory and probably Foretrress do that better if you want a suicide hazard lead? I mean, sure it can do that, but there are at least 2 others in OU that can do better so kinda doesnt matter when you rank it.

They do not require a lot of support to function -- what you are failing to understand is that Rain has so many good setters and so many good abusers it is an actual playstyle, of which Dra, Kabu, Oma and - arguably controversially - Swampert are by far the best abusers.
Yes they are only viable on that one playstyle; but that's why they're nowhere above the B rankings. I get the feeling you've never gone up against or used a good rain team before; it is ridiculously destructive.

I did acknowledge rain effectiveness in my post. And to say it again: "effective when done right but the cost is too much imo".

 

[Invok3r]

Omastar has a niche due to the access of ice beam, which lets it have a great matchup vs lead lando-t, and chomp. It can also spam scald and fish for burns before it dies, which none of the other leads can do.

Edit: Forgot to mention that i got #10 on ladder a couple months ago with omastar ho, so I have a lot of experience using it.

 

[Canned Bread]

Kingdra should drop to B
Kabutops and Omastar should drop to B-
Mega Swampert should drop to C+

All four depend heavily on rain to function. That means you have to dedicate around 2 other Pokemon on your team to support them. That opportunity cost limits team building pretty severely. And although rain is very effective when done right, the cost is still too much imo.

On why they are ranked differently:
- kingdra is can sort of function outside of rain with the critDra set and is the best rain abuser imo (B rank)
- kabutops cannot do anything without rain, still not that threatening under rain but can pull off a spin or an aqua jet even outside of it in a pinch so B- rank
- omastar also cannot do anything without rain but has great offensive presence under rain so B-
- mega swampert cost you your mega slot, waste 1 turn on your rain on the turn it mega evolves, and does not hit too much harder than kabutops. There are better megas to usecon a rain team. (C+ rank)

I can say more but I think you get my idea here: these four require lots of support to function. Drop them

"Lots of team support" is an outright lie. All they need is Politoed. That's it. If maybe they were solid but unspectacular in rain I'd agree with a drop, but they're not. Their raw power is just ridiculous and all they need to rip a team apart is Politoed. They should stay where they are.
Edit: Ninja'd

 

[Obliviate]

Although I support Shaymin rising to C/C-, I think you exaggerate the usefulness of Seed Flare. It isn't as spammable as Scald because it only has 8 PP. You also didn't mention its inaccuracy in contrast to Scald making it less reliable.
But still, I think Shaymin is a great mon which definetely deserves to be somewhere in the C-ranks. Not being weak to Dark types is huge, its movepool and defensive stats are also great.

 

[Kurona]

I did acknowledge rain effectiveness in my post. And to say it again: "effective when done right but the cost is too much imo".

I find the 'cost' argument silly from time to time but this is just downright incredible. I don't understand what sort of cost there is when doing it; you're not exactly sacrificing anything -- you might as well say Mega Metagross should move down because you have the cost of not fitting in well on a Stall team. Rain is an incredibly effective playstyle and I fail to see what cost there is for using it. While Kabu, Oma, Dra and Pert are relatively controversial in whether they should be B or B+, they should never drop below B because rain is just that effective and these four are arguably the best members. Please define what exactly you mean by 'cost' because I honestly have no idea what you mean by that word which seems to me to just be thrown around far too easily as of late.

 

[Sergeant Spooky]

Kingdra should drop to B
Kabutops and Omastar should drop to B-
Mega Swampert should drop to C+

All four depend heavily on rain to function. That means you have to dedicate around 2 other Pokemon on your team to support them. That opportunity cost limits team building pretty severely. And although rain is very effective when done right, the cost is still too much imo.

On why they are ranked differently:
- kingdra is can sort of function outside of rain with the critDra set and is the best rain abuser imo (B rank)
- kabutops cannot do anything without rain, still not that threatening under rain but can pull off a spin or an aqua jet even outside of it in a pinch so B- rank
- omastar also cannot do anything without rain but has great offensive presence under rain so B-
- mega swampert cost you your mega slot, waste 1 turn on your rain on the turn it mega evolves, and does not hit too much harder than kabutops. There are better megas to usecon a rain team. (C+ rank)

I can say more but I think you get my idea here: these four require lots of support to function. Drop them

Perhaps the Rain support requirement is what's keeping them B+/B and not something in the A ranks. Many people will tell you that Rain is a very effective archetype, and it's due to the insane power of Swift Swimmers.

Also critdra sucks, and Mega Swampert's bulk makes it better than Kabutops (imo).

 

[ChipButty]

Kingdra should drop to B
Kabutops and Omastar should drop to B-
Mega Swampert should drop to C+

All four depend heavily on rain to function. That means you have to dedicate around 2 other Pokemon on your team to support them. That opportunity cost limits team building pretty severely. And although rain is very effective when done right, the cost is still too much imo.

On why they are ranked differently:
- kingdra is can sort of function outside of rain with the critDra set and is the best rain abuser imo (B rank)
- kabutops cannot do anything without rain, still not that threatening under rain but can pull off a spin or an aqua jet even outside of it in a pinch so B- rank
- omastar also cannot do anything without rain but has great offensive presence under rain so B-
- mega swampert cost you your mega slot, waste 1 turn on your rain on the turn it mega evolves, and does not hit too much harder than kabutops. There are better megas to usecon a rain team. (C+ rank)

I can say more but I think you get my idea here: these four require lots of support to function. Drop them

These Pokemon shouldn't drop just because they need rain to function. Rain Offense is a very potent playstyle and you need some experience with it to appreciate its effectiveness. If you're building a team with Swift Swimmers, chances are your team was already built with Rain in mind and so it doesn't limit teambuilding in that sense. Of course you're going to need support from other team members; Politoed and Swift Swimmers can't handle some Pokemon all by themselves. I don't know why you propose that Kingdra should move down when you mention that it is an effective Swift Swimmer as that's why it should stay in B+ (CritDra just isn't that effective compared to SS Kingdra). Kabutops and Omastar are massively threatening in the Rain; of course they aren't going to be as effective outside of rain, that's why you put them on Rain teams in the first place. Swampert shouldn't move down just because of those downsides; it's a great Rain Mega thanks to great bulk, an Electric immunity and Fighting coverage (STAB EQ is pretty darn nice too). Sorry if this sounded a bit mean, but I think the Rain sweepers are fine in their current rankings.

 

[North Gate]

Kingdra should drop to B
Kabutops and Omastar should drop to B-
Mega Swampert should drop to C+

All four depend heavily on rain to function. That means you have to dedicate around 2 other Pokemon on your team to support them. That opportunity cost limits team building pretty severely. And although rain is very effective when done right, the cost is still too much imo.

On why they are ranked differently:
- kingdra is can sort of function outside of rain with the critDra set and is the best rain abuser imo (B rank)
- kabutops cannot do anything without rain, still not that threatening under rain but can pull off a spin or an aqua jet even outside of it in a pinch so B- rank
- omastar also cannot do anything without rain but has great offensive presence under rain so B-
- mega swampert cost you your mega slot, waste 1 turn on your rain on the turn it mega evolves, and does not hit too much harder than kabutops. There are better megas to usecon a rain team. (C+ rank)

I can say more but I think you get my idea here: these four require lots of support to function. Drop them

A lot of support is a lie, as it was pointed out. Politoed is all it needs, and rain is a very good archtype that just kills hyper offense because of the raw unbridled speed and power of Swift Swim abusers. ((Not sure about the HO thing, because I don't use rain that much.)) Kingdra is really good as a swift swimmer, the power of Waterfalls/Scalds/Hydro Pumps is insane coming from it, and its typing is kinda cool too. The only real good team support (besides toed) you'd need for most Rain abusers is a Ferro check. Omastar is really cool as a suicide lead all in its own, with access to Toxic Spikes, Spikes, and Rocks as stated above, and Omastar smacks other SLeads with its Ice Beams, and Scalds coming from it do enough and can deter many physical attackers. ((R.I.P UU Omastar.)) All in all, these are very good. Although Mega Swamp is a little underwhelming imo, so I have no comment on it.
Also this is the first time I've posted here. Yay.