The best 3 attacks moveset is DD / Dragon Claw / Flare Blitz / Earthquake. With this moveset, you basically spam Dragon Claw and Flare Blitz only when you need to. So no, you don't need to Outrage. Dragon Claw is damn powerful after a boost, 2HKOing stuff like Vaporeon, Jellicent, and Rotom-W with ease. Oh, and Rotom-W: it's the most common Pokemon in OU, and Megazard X sets up all in its face. Genesect? Unless it's CB ESpeed, Megazard X goes to town. Aegislash? Fat chance that can stay in at all. Mega Venusaur? lol. Lucario can't do shit once it's boosted, and can't switch in at all. So right there, 4/5 of S Rank destroyed by it.
A+ Rank. Heatran is destroyed by EQ. Megazard Y loses to +1 DClaw. Non-Scarf Garchomp get stomped. Manaphy has a 62.5% to be OHKOed by Dragon Claw after SR, and can't switch into anything. The aforementioned Rotom-W dies to it. Mega Pinsir loses. Landorus loses. So, like 6.5 (because ScarfChomp is common)/10 Pokemon in A+ Rank are destroyed by it.
Virtually all of A Rank besides Landorus-T, Gliscor, Choice Scarf Terrakion, and Azumarill gets murdered. That's like 18.5/23 right there.
There are certainly ways to handle Megazard X in OU -- some of them I mentioned from the ranks I covered -- but the fact remains that Megazard X fulfills the S Rank definition.
I've established that Megazard X can sweep significant portions of the metagame. It also requires little support to do so -- literally all you need to do is wear down Landorus-T and Gliscor throughout the battle, which isn't really that hard, as Megazard X's Dragon Claw/Flare Blitz, even after Intimidate, does a number. Gliscor requires a bit more support to take out, but the point remains. You also need to eliminate Azumarill, and a couple other things, like faster Scarfers. Still, that's not that hard, and requires little dedicated support. It's only a few things that Megazard X has trouble with. Defog support is nice, but not 100% necessary.
It is also versatile. A set with Roost can heal up and thus protect itself revenge killing. It can run Outrage as an insanely powerful Dragon STAB. A bulky set with Will-O-Wisp can serve as a good check to a variety of things that still hits very hard, and can potentially provide Defog support. Plus, it's unpredictable, as the opponent doesn't know whether it is one of those sets, or even Megazard X at all (until it Mega Evolves it's a guessing game as to whether it might be Megazard Y). This unpredictability and versatility only add to how Mega Charizard X is a clear
S Rank.
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I want now to address the
Mega Pinsir discussion: it deserves
S Rank. A lot of people have covered it nicely. I'll just quote a few posts here:
These points sum up the argument excellently. Mega Pinsir sweeps through so much of the metagame and is just overall a major force to be reckoned with. Sure, there are offensive checks, and sure, it's 4x to weak to SR (though not on the first switch-in before it Mega Evolves, so SR really isn't that a big of a deal), but it's a sweeper with extremely powerful attacks, STAB ~53 BP priority move, and the potential to eliminate a portion of blocks to it depending on whether it runs CC, EQ, or Stone Edge in the last slot, make it a true top-tier OU sweeper and one of the most devastating threats around -- a true S Rank.
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The issue with Lucario is just...it's too slow, and Extreme Speed makes up for that to an extent, but not fully. It's a difficult Pokemon to work with, and requires a pretty significant amount of support. It's really not that difficult to deal with, as the metagame packs a good number of checks and counters to it...including basically anything faster that can live a +2 Extreme Speed, which is a significant portion of threats, and Talonflame. This is not to say that Lucario isn't good -- it just isn't B Rank material. B- suits it well. If you want to argue about moving Infernape down, then that's another story, but don't use Infernape's placement as a judgment for Lucario.
I'm honestly surprised to see
Diggersby so low. Dice covers it pretty well:
Diggersby is a powerful sweeper with priority, and is really, really dangerous. It also has versatility in that it can run an effective Choice Scarf revenge killing set with the invaluable U-turn, and a deadly Choice Band set that boasts immense immediate power. Diggersby is really strong, and
B would make a good place for it.
The suggestion for Ferrothorn seems on target, too.
Agreeing with
sidakarya on Zapdos. It's a really good Pokemon in the metagame, serving as a great way to handle a number of things, including special Mega Lucario, a threat that's almost impossible to counter otherwise.
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B Rank looks rather crowded, and I think a few things can be sorted out:
Mega Absol for B-: In all my experiences fighting Mega Absol, it's really never been that difficult to deal with. Magic Bounce is a nice ability, but Mega Absol has trouble against many hazard users. It isn't too complicated to check either, and has an unfortunate inability to run Knock Off + Play Rough, its best coverage move. Access to Fire Blast and Ice Beam is nice, and there's no denying that Mega Absol is a veritable offensive threat with an SD boost, but it's just not all that threatening.
Agreeing with previous posts on
Espeon for C+. There's not a whole lot else to say here.
Entei for B-: I just really don't see Entei as B Rank-level threat. Sacred Fire is indeed an awesome move, and priority Extreme Speed is excellent, but Entei just really isn't that complicated to check. Your bulky Ground-type (Landorus-T/Gliscor), your bulky Water-type (Vaporeon/Slowbro/Rotom-W), both Megazards, Talonflame, Manaphy, etc. are so detrimental to it. Although, they don't all appreciate a Sacred Fire burn, they can still switch in, and Entei isn't that great at breaking them. All in all, while the buff in Sacred Fire and reliability/burns it gives are great, it isn't enough to put Entei all the way up in B.
Sylveon for B+: I'm really surprised to see Sylveon down in B Rank, below Clefable no less. Sylveon's special walling capabilities are just excellent. It serves as a great Dragon- and Fighting-type check, destroys Aegislash without a Steel-type move, walls Deoxys-S with ease, handles Thundurus and Landorus good, counters Greninja...Sylveon boasts excellent walling capabilities. Walling isn't all Sylveon is good for though -- I wouldn't be nominating it for B+ if this was so. It also boasts insane utility. Wish is a great move, supporting teammates, and with Protect gives Sylveon reliable recovery. Protect lets Sylveon scout and stall weather turns, and overall eases prediction hugely. Against a Genesect and want to check if it's gonna U-turn or Iron Head? Protect. That's just one example. It also provides invaluable cleric support -- there aren't that many clerics in this metagame either. Not only this, but Sylveon has decent power, even with a bulky set, given Pixilate-boosted Hyper Voice, and can boost to handle special threats even better, hit harder, and sweep late-game with its checks and counters removed. This is not even taking into consideration the excellent Choice Specs set, which hits hard with Hyper Voice, has Psyshock to murder Mega Venusaur, and can utilize a powerful Pixilate-boosted Echoed Voice given the opportunity. There's also a Choice Scarf set, which can revenge kill decently and take advantage of Echoed Voice, too. All in all, Sylveon is bursting with qualities that make it worth B+.
Jellicent for B-: Jellicent really took a hit in XY. It just can't...wall that much anymore, and its placement in B Rank surprises me. Handling Mega Lucario is indeed an excellent trait, but it loses to so many top threats. Setup fodder for Megazard X, loses to Megazard Y's Solar Beam, crushed by Landorus-I, murdered by Thundurus-I, eliminated by Manaphy's Energy Ball...there's just so much it can't do in OU; B- fits it. Honestly, I could see it in
C+. B- is almost being too generous, but that's what I'll nominate it for, as it does have some perks.
Krookodile for B-: I love Krookodile, and have used it with nice results, but B Rank is just too generous to to it. Krookodile boasts STAB Knock Off and Earthquake, as well as access to Stealth Rock and Taunt with Intimidate, allowing it to function as an effective defensive check to various things, and can even run a deadly offensive set with Moxie. However, it's weak to Fairy, Fighting, and Water -- three common types -- and is boned by Mega Venusaur. It can handle a solid amount of things, but it isn't too complicated to wear down, lacking recovery out of Leftovers. Although it is difficult to wear down and effective if you know how to use it, I plainly don't see Krookodile as a B Rank threat. It also faces competitionB- fits it much better.
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Ctrl + F
Vaporeon, nothing found. I've used Vaporeon extensively, and it has a solid niche in the OU tier. Boasting sizable defenses, Vaporeon can take hits from a good chunk of things well, including but not limited to everything from Genesect but Thunderbolt, Aegislash, Deoxys-S, Heatran, Talonflame, Gengar, Keldeo, Azumarill, Mega Mawile, bulky Landorus-T, and more. It too, like Sylveon, is bursting with utility. It can spread burn with Scald, cripple bulky Pokemon like Rotom-W with Toxic, provide cleric support, and even phaze, depending on what you choose for the last moveslot. It can also provide Wish support and scout/stall weather turns/get reliable recovery with Protect. Unfortunately, its physical bulk isn't /amazing/, in addition to some other flaws. It fits the definition of
B Rank excellently imo.
Vaporeon fulfills a good defensive niche, able to handle a solid array of threats in the OU metagame. It has some flaws, and is setup bait for certain sweepers without Roar (few physical ones appreciate a Scald burn, though). Overall, B fits it well based on this definition.
B or B- for Vaporeon.
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On
Moltres:
C is the best fit for it, I think. I played with it for a good, maybe, 15 battles (the defensive set), and it just isn't that great. With SR, it is unreliable, too. However, with an offensive set it can hit pretty hard, and with a SubToxic Pressure stalling set it can serve as a great staller on teams dedicated to keeping SR off the field. It has some pretty crippling flaws, including the fact that it's just...not that bulky, but it can fit into C Rank well. Also, yes, it is getting an OU analysis.
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Breloom just really lost out in this metagame. It's handled really easily by so, so much. Just look at the Pokemon in S, A+, and A Rank, which we'd consider the top-tier OU Pokemon. It's destroyed by much of S Rank, including the extremely prevalent Aegislash. Pokemon like Megazard Y that resist both of its STABs are common, and though Rock Tomb covers that to an extent, it doesn't really do the whole job. Spore went from an uncounterable sleep move to a move taken easily by Grass-types, especially the very common Mega Venusaur, and Overcoat Pokemon (Mandibuzz and Forretress). Overall, Breloom isn't that good this generation. It has its uses, but not many. It's not that bulky and uncomplicated to wear down/check/counter, and there are a number of top OU threats, such as Mega Lucario, that eclipse it as a powerful physical attacker, too. Above like
C+? I can't see that.
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There's one other Pokemon that isn't on this list, but absolutely should be, and that's
Kyurem. I always figured it was outclassed by Kyurem-B, basically, and didn't think SubRoost was that good. Damn, how wrong I was. I gave it a spin on the OU ladder, and the results were absolutely astonishing. Kyurem boasts 125/90/90 bulk, which is just awesome, and stellar coverage in Ice Beam and Earth Power. With Substitute and Roost, it can stall extraordinarily well, getting up Substitutes with ease against a good amount of things, including Rotom-W. With Pressure, it can stall out things like Hydro Pump, Fire Blast, and Draco Meteor with ease. Base 130 Special Attack makes it PLENTY powerful, and base 95 Speed is enough to outrun a decent portion of the metagame. With these traits considered, I think Kyurem deserves
B Rank.
I think that covers everything.
EDIT: mmm missing one thing
Mega Medicham for B or B+: I'm astonished to see Mega Medicham in A, truth be told. I've talked to numerous people, and pretty much the consensus among all of them is that it's powerful, but just way too frail. This frailty combined with not that great Speed is so crippling to it that I can't see it as an A Rank threat. Other Pokemon can live with lower Speed, but Mega Medicham doesn't have any of the qualities that make up for it. It's an offensive titan, but the fact that it can't take a hit to save its life is just really bad for it. B+ is pushing it, imo, but others might disagree, so leaving that out there.
EDIT2: And, Thundurus-T is really threatening. It's a nice sweeper, and has a niche over Thundurus in more power and its ability. Like X5Dragon proposed,
B Rank imo.
