Other XY OU Viability Ranking Thread (V2) (Last update on post #5189)

[BurningFury101]

Gary2346

Deoxys-S

Deoxys-S brings in a whole new dimension of versatility. Boasting powerful Psycho Boosts, unmatched speed, and unresisted coverage, no Pokemon is safe from this great monster. Deoxys-S can set up rocks, and spikes, almost always setting two layers of hazards, and add on immense offensive pressure in few turns. Deoxys-S also runs an effective Life Orb revenge-killer set. With it's blistering speed that can outspeed base 100 Scarfers, it's one of the only Pokemon in existence that can revenge-kill while being able to switch moves, coming in with great moves including Psycho Boost, HP [Fire], Knock Off, BoltBeam, and Superpower. Although it's bulk is absolutely horrific (Any powerful hit will bring it down to it's Focus Sash, or kill it), no player should be discouraged to used Deoxys-S as it's suicide lead role, and it's revenge-killing set will more than make up for it's poor bulk.

If you want anything changed please feel free to message me. I'm fine if you don't like it and just want someone else to write it, though.

 

[alexwolf]

Btw, feel free to write descriptions about ranked Pokemon that don't already have, but make sure to tag Gary so that he can read them, and if he wants he will add them.

 

[deepbluejeer]

Going to reserve Sylveon. Gary2346

Hide

Sylveon is one of Generation VI's new additions to the Fairy-type. As one of the lucky Pokemon who received the coveted typing, Sylveon has many useful tools at its disposal. Its high Sp. Def., decent HP, and access to Wish and Heal Bell make it a usable cleric for your team. However, what makes Sylveon stand out from other Pokemon that can perform the same role is its offensive presence: with its ability, Pixilate, Hyper Voice becomes a 117 BP STAB attack that goes through Substitutes, which actually allows it to threaten many key threats in the metagame - in particular Kyurem-B, whose best set only manages to 3HKO while Sylveon 2HKOs with Hyper Voice. In fact, having a strong, spammable STAB even allows it to run offensive sets like Choice Specs or RestTalk + Calm Mind. While it is slow and somewhat weak on the physical side, Sylveon's support is invaluable for many teams.

 

[Salt]

Gary2346, I'll reserve Crawdaunt.

Edit:

Crawdaunt

The one thing that defines Crawdaunt is power. With a base 120 Attack stat, Adaptability, and high powered moves in Crabhammer and Knock Off, Crawdaunt is extremely stong. The crab also has access to Aqua Jet, making it a useful revenge killer of frail and weakened threats, and Swords Dance to become a truly fearsome stallbreaker. Beyond this, though, there isn't much that Crawdaunt has going for it, and it also has quite a few flaws. Crawdaunt's bulk is pathetic, meaning it can't switch in on most attacks in OU and it's extremely easy to force out or revenge kill. Crawdaunt is also very slow, which means it struggles against offensive teams. Though Crawdaunt's flaws cannot be overlooked, it can dish out heavy damage in the right hands.

 

[Sergeant Spooky]

Gary2346 reserving Chesnaught and Mandibuzz
---------

Hide

Chesnaught's Grass/Fighting typing, while giving it six weaknesses, gives it many resistances such as Ground, Rock, Water, and Dark that are valuable in the meta. This, combined with its superb 88/122 physical defenses and STAB Fighting attacks, allows it to serve as a counter to dangerous threats like Mega Gyarados, Mega Tyranitar, Excadrill, and Bisharp. Its ability in Bulletproof makes it immune to "ball and bomb" moves, including Shadow Ball, Focus Blast and Sludge Bomb, which notably allows Chesnaught to beat many Aegislash and Gengar sets. Chesnaught has Leech Seed, a very valuable move for a defensive Pokemon, and combined with its signature move, Spiky Shield, which acts as a protect that deals damage on contact, Chesnaught can wear down anything it can't hurt directly. It also has reliable recovery (sans Rain or Sand) in Synthesis, and it can use Spikes. While its weaknesses make it vulnerable to many common Pokemon, Chesnaught is still very capable of handling many top threats.

Hide

Mandibuzz is very bulky and hard to take down. Its physical bulk is greater than Skarmory's, and its special bulk is only slightly worse than its physical bulk. While it does not have Skarmory's wide range of resistances, its Dark typing gives valuable resistances to Ghost and Dark, and its secondary typing makes it neutral to Fighting attacks. This makes Mandibuzz one of the best counters to powerful Ghost and Dark attackers, such as Aegislash. Furthermore, its raw bulk and STAB Foul Play, which uses the target's Attack stat, allows it to counter many physical attackers. Mandibuzz also has Knock Off, which allows it to remove items; Defog, to remove hazards; Taunt, which, combined with its above average speed for a wall, allows it to mess with opposing defensive Pokemon; and other viable moves like Whirlwind, Toxic, U-Turn, and Tailwind. Overcoat is also a decent ability, giving Mandibuzz a blanket immunity to Sand/Hail damage, as well as powder moves like Spore and Sleep Power. While possessing only a small number of resistances and a vulnerability to Stealth Rock, Mandibuzz more than makes up for it with huge bulk, key resistances and a good movepool, securing its place as the best defensive Dark type and one of the best support/defensive Pokemon in the meta.

 

[Banded Blissey]

Mega Gyarados for S rank
So we know how threatening bulky Dragon Dancers are. Mega Charizard X, and Mega TTar are representative of this. Now lets say you mashed both of them together. ta-dah! You have mega gyarados. Discounting abilities, it is THE strongest of the 3 as it can afford to run adamant. Its list of counters is really small, with them being limited to: Ferrothorn, Skarmory, and Mandibuzz. And that's just one dragon dance! After 2, the list is cut down to just Skarmory. And it can feasibly get to 2 as it has tremendous bulk and offensive presence. It has mold breaker EQ to shit on Rotom-W, Mold breaker Ice Fang to shit on Venu, and Mold Breaker just makes Unaware users cry. And Bisharp was recently inducted to S, so it would make sense Megados would too, right? It is WAY more threatening of a sweeper than Bisharp, and it just breaks offensive teams. It does have flaws that its checks are fairly common, but that doesn't stop it from being among the deadliest DDer there is.
Gary2346
MEGA GYARA BELONGS IN S, IT IS WAY OVERDUE

 

[Terrakion.]

Mega Charizard is still the more threatening Dragon Dancer. Maintaining for firepower, better defensive typing allows it to sweep teams after 1 Dragon Dance. Charizard doesn't have to worry about Will-O-Wisp or any Scald burn chances. Even though Mold Breaker Gyarados ignores things such as Unaware Clefable and Quagsire, Charizard easily breaks through them 2HKOing both of them.

 

[Banded Blissey]

Mega Charizard is still the more threatening Dragon Dancer. Maintaining for firepower, better defensive typing allows it to sweep teams after 1 Dragon Dance. Charizard doesn't have to worry about Will-O-Wisp or any Scald burn chances. Even though Mold Breaker Gyarados ignores things such as Unaware Clefable and Quagsire, Charizard easily breaks through them 2HKOing both of them.

I didn't say it as better, I said it was a mix of the 2

 

[Terrakion.]

I didn't say it as better, I said it was a mix of the 2

Even if you didn't ( Which you did "its the strongest of the 3" ), Mega Gyarados needs support behind it, less than what Charizard X needs to do what they do. Hell, they are all threatening? Charizard X has better Wallbreaking capabilities and can switch in and set up on things. Gyarados can't always switch in due to its horrible defensive typing.

 

[skies]

Since I've done two, I'll take on Mega Manectric and Terrakion, along with Chansey.

On the subject of Mega Manectric, I'm nominating it go from B ---> B+ / A-.
Mega Manectric is blazing fast with base 135 Speed, it also is only ~4% weaker than Life Orb Manectric is. If I did this correctly, it should have around 130 Defense after Intimidate:
-1 0 Atk Mew Zen Headbutt vs. 0 HP / 0 Def Mega Manectric: 69-82 (24.5 - 29.1%) -- 99.8% chance to 4HKO
0 Atk Mew Zen Headbutt vs. 0 HP / 0 Def 130 Base Defense Mega Manectric: 69-82 (24.5 - 29.1%) -- 99.8% chance to 4HKO
So, correct me if I'm wrong, but on any Pokemon it switches into, Mega Manectric instantly gains a stat spread of 70 / 75 / 130 / 135 / 80 / 135. It has an extremely powerful Thunderbolt and also has access to many interesting coverage options such as Hidden Power [Ice] and Overheat. It makes an exceptional pivot with Volt Switch + Intimidate and blends perfectly with Landorus-T forming an infamous core. Mega Manectric is a very good Pokemon, however, the problem with it is that it is always left being walled by something, it's always walled by Mega Venusaur, Tyranitar, and Chansey, while if it chooses Hidden Power [Ice] it is walled by Quagsire and Latias, while if it chooses Hidden Power [Grass] it is walled by Kyurem-B, Garchomp, and Dragonite. I can keep going on with things that wall Mega Manectric, but that's no fun! Another issue is you're stuck with 105 Speed until you Mega Evolve, which can be very problematic. On the bright side, if you switch into a Electric-move, Mega Manectric becomes insanely powerful! Mega Manectric's coverage is quite amazing though and with proper team support it can plow through offensive teams and slower teams, even fast ones too, because hell, it is faster than most! For the reasons of a great blend of power and pseudo-bulk, I believe that Mega Manectric belongs in either B+ or S-.

Terrakion
Terrakion, the infamous swordsman, makes a return to OU this generation! Terrakion is a phenomenal Pokemon that can perform many different roles from Lead, to Swords Dance, to Choice Scarf. Terrakion has a sky-high Attack stat of 129, backed by a base Speed of 108 that allow it to outspeed the majority of the tier. Another amazing feature of Terrakion is its STAB moves which are unresisted by any common OU Pokemon bar Mega Medicham and Aegislash, who is taken care of thanks to Earthquake. Terrakion has very few counters, the best being Landorus-T, Gliscor, and Slowbro, the former two being handled by Hidden Power [Ice] on lure sets. Finally, Knock Off just made Terrakion better as if it switches in on a Knock Off it gets a +1 thanks to Justified. Terrakion is truly deserving of its title of a 'Legendary Pokemon'!

Chansey


Gary2346

 

[Banded Blissey]

Even if you didn't ( Which you did "its the strongest of the 3" ), Mega Gyarados needs support behind it, less than what Charizard X needs to do what they do. Hell, they are all threatening? Charizard X has better Wallbreaking capabilities and can switch in and set up on things. Gyarados can't always switch in due to its horrible defensive typing.

Strong =/= better

 

[Aragorn the King]

Update time

Changes suggested in this thread:

Gothitelle: Unranked ---> B-
Shuckle: Unranked ---> B-
Galvantula: B- ---> C+
Weavile: Unranked ---> C+
Banette (Mega): D ---> C
Reuniclus: Unranked ---> C+
Cresselia: Unranked ---> C
Salamence: C+ ---> C
Hydreigon: Unranked ---> C+
Durant: Unranked ---> C+
Haxorus: Unranked ---> C+
Umbreon: Unranked ---> C
Amoonguss: Unranked ---> C
Zoroark: Unranked ---> C-
Gorebyss: Unranked ---> C
Hawlucha: Unranked ---> C-
Nidoking: C- ---> D
Milotic: Unranked ---> C
Tornadus: Unranked ---> C
Toxicroak: Unranked ---> C
Omastar: Unranked ---> C
Exploud: Unranked ---> D
Venusaur: Unranked ---> C+
Kyurem: C+ ---> C

Changes from the VR thread:

Bisharp: A+ ---> S
Deoxys-D: A+ ---> S
Heatran: A+ ---> A
Latias: A ---> A-
Suicune: B+ ---> B
Sylveon: B+ ---> B
Rhyperior: C ---> B-
Volcarona: B ---> B-
Alakazam (Mega): C+ ---> B-

Did you guys decide on a ranking for Seismitoed yet? It's the only Pokemon that still needs to be ranked. I think its niche as a Rain Sweeper immune to TWave is immense, however its lack of extreme power would probably make it a C ranked threat.

EDIT: Chesnaught I totally agree. It works fabulously with Landorus-T, and is a nuisance for any bulky offensive team to face. It hates Bisharp, Thundurus, and Gardevoir, but other than that, very few easily handles it. If you think you can send something in to take an electric move, it will just Volt Switch right out. To be honest, I view it as an A rank threat when I'm teambuilding, but that's just me. I guess A- would probably suit it more, maybe even B+. Anything but B or lower.

EDIT 2: I still have some ranking changes I want, but one major one is Blissey for D rank. It literally has no niche. Common arguments against it are it's less troubled by Knock Off, which isn't honestly true considering a) it can't take one well and b) loses its leftovers, the only actual reason to use it, that it doesn't take sandstorm damage, and it has a better than terrible special attack, but none of those are reasons to use it when there is a much better option, Chansey. Chansey's defensive stats are the equivalent of 250/31/182, which are far better than Blissey's 255/10/135, and allow Chansey to become a successful mixed wall. Blissey really can't do anything notable, and fits in perfectly with the D rank definition. If it weren't OU, I honestly wouldn't rank it.

 

[fleurdyleurse]

I'll reserve Jirachi.
Gary2346
Edit:

Jirachi

Once a top tier threat in OU, Jirachi no longer holds the throne of being one of the most versatile Pokemon. This is due to the buff to Ghost and Dark which makes Jirachi’s typing defensively weak, and also the Knock Off buff which makes it hard for Jirachi to switch in against many of the top-tier threats. It also cannot switch in against the behemoths of the tier in Mega-Charizard-X and Mega-Charizard-Y. Furthermore, many of the new threats either introduced in Gen VI or released from Ubers have a way to hit it without resorting to using obscure moves. However, Jirachi does possess a large movepool which has utility in Stealth Rock, Wish, Healing Wish, Rain Dance, dual screens and Thunder Wave which allow it to support it’s team well. It also has a large offensive movepool which includes but is not limited to Iron Head, the elemental punches, Thunderbolt, Body Slam, Psyshock, and U-turn and when some of it’s moves are coupled with it’s ability, Serene Grace, Jirachi can cause frustration to the opponent. Overall, Jirachi is not as powerful and easy to use as it once was but must still be accounted for.

Gary2346

 

[Flamer]

Since I've done two, I'll take on Mega Manectric and Terrakion, along with Chansey.

On the subject of Mega Manectric, I'm nominating it go from B ---> B+ / A-.
Mega Manectric is blazing fast with base 135 Speed, it also is only ~4% weaker than Life Orb Manectric is. If I did this correctly, it should have around 130 Defense after Intimidate:
-1 0 Atk Mew Zen Headbutt vs. 0 HP / 0 Def Mega Manectric: 69-82 (24.5 - 29.1%) -- 99.8% chance to 4HKO
0 Atk Mew Zen Headbutt vs. 0 HP / 0 Def 130 Base Defense Mega Manectric: 69-82 (24.5 - 29.1%) -- 99.8% chance to 4HKO
So, correct me if I'm wrong, but on any Pokemon it switches into, Mega Manectric instantly gains a stat spread of 70 / 75 / 130 / 135 / 80 / 135. It has an extremely powerful Thunderbolt and also has access to many interesting coverage options such as Hidden Power [Ice] and Overheat. It makes an exceptional pivot with Volt Switch + Intimidate and blends perfectly with Landorus-T forming an infamous core. Mega Manectric is a very good Pokemon, however, the problem with it is that it is always left being walled by something, it's always walled by Mega Venusaur, Tyranitar, and Chansey, while if it chooses Hidden Power [Ice] it is walled by Quagsire and Latias, while if it chooses Hidden Power [Grass] it is walled by Kyurem-B, Garchomp, and Dragonite. I can keep going on with things that wall Mega Manectric, but that's no fun! Another issue is you're stuck with 105 Speed until you Mega Evolve, which can be very problematic. On the bright side, if you switch into a Electric-move, Mega Manectric becomes insanely powerful! Mega Manectric's coverage is quite amazing though and with proper team support it can plow through offensive teams and slower teams, even fast ones too, because hell, it is faster than most! For the reasons of a great blend of power and pseudo-bulk, I believe that Mega Manectric belongs in either B+ or S-.

Dammit I thought I was the only one who noticed MegaMan+Lando Calrissian-T.

Definately agree with you here. Mega-Manectric has so much utility this gen, with an amazing speed tier, Intimidate to check Physical threats not named Bisharp, and pretty darn good coverage in Flamethrower and Overheat. The fact that it is walled depending on its HP is an issue but that's why its not being nominated for S.

 

[MQJinx]

I think we should have some discussion about the placements of Gastrodon and Barbaracle.

Gastrodon can check VolTurn and any Thundurus lacking Grass Knot, as its Ground typing is the only reason to use it over Rotom-W. It can also check some rain threats due to Storm Drain. Its physical bulk and Recover grant it uses as a tank. However, weakness to Toxic and iffy offenses can really hurt. C Rank imo.

Barbaracle can really wreck havoc after a smash, that 108 Speed is required for a scarfer to outspeed it at +2. Tough Claws along with Water + Rock STABs already providing decent coverage alone. Its main concern is its priority weakness and anything it can't land SE hits on, and being forced to choose between elminating Aegislash or eliminating Ferrothorn. C Rank imo.

 

[DoABarrelRoll]

Why was Volcarona dropped in B-? If azumarill is one of the reasons, remember volc can use giga drain to get past it. If Azu tries to revenge kill with Aqua Jet, it'll get burned 30% of the time. Volcarona can still set up on many threats: aegislash, ferrothorn, (mega) scizor ,heatran (if it has HP Ground), (Mega) Manectric, some lati@s, or even mega venusaur with sleep clause activated. Volcarona also benefited from the weather nerf, in the sense that drizzle is no longer everywhere, as well as the Defog buff.
So basically, Volcarona needs Defog support + something to get rid of Talonflame and Bisharp. B/B+ rank is in my opinion more appropriate

 

[Baharoth]

Even if you didn't ( Which you did "its the strongest of the 3" ), Mega Gyarados needs support behind it, less than what Charizard X needs to do what they do. Hell, they are all threatening? Charizard X has better Wallbreaking capabilities and can switch in and set up on things. Gyarados can't always switch in due to its horrible defensive typing.

Water/Flying is a rather good defensive typing and Gyarados has Intimidate to make switching in and setting up even easier. What people always forget when talking about mega Gyara is that he doesnt have to evolve immediately unlike other mega evolutions. You wont go mega unless you have to that means that most of the time you will switch in, you will be in base form benefitting from the better typing.

Mega Charizard X might have more firepower when he uses Flare Blitz and Outrage (he needs adamant outrage to break Quagsire) but that power comes at a prize in form of heavy recoil or beeing locked into Outrage. Gyara doesnt have that problem and can break those walls as well due to Mold Breaker, with Taunt he can break basicly every wall outside of Ferrothorn. Gyara combines firepower, massive bulk, two good abilitys one to switch in and set up and another to sweep, good typing AND the ability to switch the typing and with it his checks and counters and he doesnt need as much support as Charizards as he isnt so weak against SR. He isnt the best in terms of raw power but his bulk and flexibility make him the best DDer in the meta imo. Banded Blissey is absolutely right, Gyara has power similar to that of ZardX and bulk similar to TTar just with better typing and the ability to switch his typing.

 

[fleurdyleurse]

Gary2346 reserving Mamoswine

 

[Facepalmboook]

EDIT 2: I still have some ranking changes I want, but one major one is Blissey for D rank. It literally has no niche. Common arguments against it are it's less troubled by Knock Off, which isn't honestly true considering a) it can't take one well and b) loses its leftovers, the only actual reason to use it, that it doesn't take sandstorm damage, and it has a better than terrible special attack, but none of those are reasons to use it when there is a much better option, Chansey. Chansey's defensive stats are the equivalent of 250/31/182, which are far better than Blissey's 255/10/135, and allow Chansey to become a successful mixed wall. Blissey really can't do anything notable, and fits in perfectly with the D rank definition. If it weren't OU, I honestly wouldn't rank it.

C Rank: Reserved for Pokemon who can be effective given the right support, but either have crippling flaws that prevent them from consistently executing their strategy or are completely eclipsed by a Pokemon in the above ranks.

 

[Aragorn the King]

Then perhaps it's just a flaw in the definition, because as it stands, the definition of D rank is more favorable than the C rank. Empoleon has a niche, Blissey has none. Blissey is 99% outclassed and is OU, and gets to be C rank, while because Empoleon is UU and ≈ 80% outclassed, and as such it gets D. Blissey is to Chansey as Florges is to Sylveon, and yet somehow Blissey is currently C ranked and discussion on Florges is prohibited. If Blissey must be C, it should be C-, but I honestly feel it should be D. It has no use at all, and is only ranked because it has to be. Why isn't Florges ranked (sorry for bringing it up)? Because it's 99% outclassed. But, if the C rank encompasses everything that can be effective, however outclassed, Blissey and Florges both deserve C rank. However, this is not the case, and is not what I'm proposing. Both are outclassed and have no niche. Blissey is only getting ranked because it has to be. It can be effective, given the right support, but it doesn't do anything notable that something else can't do better. Does it actually deserve to be ranked? No. Not if Florges doesn't.

 

[Facepalmboook]

You don't seem to understand, Facepalmboook . He's saying there is no reason to use Blissey. It's like Kyogre vs Politoed for setting up Rain in Ubers. Kyogre completely eclipses Politoed, but Politoed still sets it up, so should it be C rank (in Ubers)? You probably shouldn't even answer that..

There is actually a huge difference between Toad vs. Kyogre and Chansey vs. Blissey. Toad is not only totally eclipsed, it's also not good in UBERS. Not only does it have way worse stats, it also lacks cruical moves. Blissey however, has all the options Chansey has and is not bad at all. The only reason why there is no reason to use Blissey is Chansey, thats the reason why Blissey should stay c+

 

[Aragorn the King]

There is actually a huge difference between Toad vs. Kyogre and Chansey vs. Blissey. Toad is not only totally eclipsed, it's also not good in UBERS. Not only does it have way worse stats, it also lacks cruical moves. Blissey however, has all the options Chansey has and is not bad at all. The only reason why there is no reason to use Blissey is Chansey, thats the reason why Blissey should stay c+

Then perhaps it's just a flaw in the definition, because as it stands, the definition of D rank is more favorable than the C rank...it has no use at all, and is only ranked because it has to be. Why isn't Florges ranked (sorry for bringing it up)? Because it's 99% outclassed. But, if the C rank encompasses everything that can be effective, however outclassed, Blissey and Florges both deserve C rank. However, this is not the case, and is not what I'm proposing. Both are outclassed and have no niche. Blissey is only getting ranked because it has to be. It can be effective, given the right support, but it doesn't do anything notable that something else can't do better. Does it actually deserve to be ranked? No. Not if Florges doesn't.

Blissey : Chansey :: Florges : Sylveon :: Machamp : Conkeldurr
Florges can effective in OU, however, every relevant thing it can do can be done better by Sylveon. Blissey can be effective in OU, however every relevant thing it can do can be done better by Chansey. The only reason Blissey has to be ranked is because it is OU, otherwise it should unranked like Florges for not having a niche. Since this is the case, D rank is where it should go.

 

[Facepalmboook]

Blissey : Chansey :: Florges : Sylveon :: Machamp : Conkeldurr
Florges can effective in OU, however, every relevant thing it can do can be done better by Sylveon. Blissey can be effective in OU, however every relevant thing it can do can be done better by Chansey. The only reason Blissey has to be ranked is because it is OU, otherwise it should unranked like Florges for not having a niche. Since this is the case, D rank is where it should go.

Sylveon can not only do everything that Florges can do, it can do more than it.
Sylveon has baton pass, dual screens and abilities that are useful in single battles.
Chansey on the other hand can't do more than Blissey. They have an identical movepool and the same abilities.

 

[Aragorn the King]

Sylveon can not only do everything that Florges can do, it can do more than it.
Sylveon has baton pass, dual screens and abilities that are useful in single battles.
Chansey on the other hand can't do more than Blissey. They have an identical movepool and the same abilities.

But stats do mean something.

Blissey's defensive stats: 255/10/135
Chansey's: 250/31/180

Chansey is a fantastic mixed wall, and can do its job whenever as long as the opponent doesn't have a STAB Fighting Move, a coverage Focus, Punch, or Knock Off.
Chansey can function against any other physical move, while blissey collapses to them all.

252 Atk Terrakion Stone Edge vs. 0 HP / 252+ Def Eviolite Chansey: 216-255 (33.6 - 39.7%) -- guaranteed 3HKO
252 Atk Terrakion Close Combat vs. 0 HP / 252+ Def Eviolite Chansey: 518-612 (80.8 - 95.4%) -- guaranteed 2HKO
252+ Atk Tough Claws Mega Charizard X Flare Blitz vs. 0 HP / 252+ Def Eviolite Chansey: 381-448 (59.4 - 69.8%) -- guaranteed 2HKO

252 Atk Terrakion Stone Edge vs. 0 HP / 252+ Def Blissey: 295-348 (45.3 - 53.4%) -- 1.2% chance to 2HKO after Leftovers recovery
252 Atk Terrakion Close Combat vs. 0 HP / 252+ Def Blissey: 708-834 (108.7 - 128.1%) -- guaranteed OHKO
252+ Atk Tough Claws Mega Charizard X Flare Blitz vs. 0 HP / 252+ Def Blissey: 520-613 (79.8 - 94.1%) -- guaranteed 2HKO after Leftovers recovery

Chansey can take any physical move well, while Blissey gets 2HKO'd by basically every one. Yes, their movepools and abilities are identical, but Blissey's poor stats compared to Chansey's prevent Blissey from doing anything to differentiate them.

 

[malomyotismon]

Gonna be honest, the only reason of any note to use blissey over Chaney, is knock off. If your team can't afford to have its items removed, - in the event you lack a mega, lack a mega capable of taking on common kock off users or in the event your mega Is koed, then blissey is preferred over Chaney. You loose much as you gained with evolute Chaney if you loose the item, while leftovers for blissey is not nearly as a huge loss. Leftovers recovery and acess to bolt beam and thrower are mainly bonuses to this fact.