Yeah, I'm going to have to agree with everyone else here and say that Infernape deserves A+; It has a huge amount of wallbreaking prowess, especially with a life orb, and can beat every other lead in the game with a sash and can defeat several of the stealth rock leads before they can even set rocks up. There are only a couple of walls in the game that can switch safely into nape, because the bulky waters that would normally switch into a Fire Blast/Flare Blitz get hit hard by Grass Knot.
For Blissey, I'm going A-. First of all, blissey can wall most of the special attackers in the tier. We know that. But it does have flaws- it's can easily become setup bait to a lot of physical attackers in the tier- Especially substitute ones, because they can simply sub up and if they run enough HP to live a seismic toss behind a sub, then you're in for something. The opponent basically gets up a free setup move. It requires support because most of the really hard-hitting physical attackers in the tier are able to break it, which means you have to pack more walls to wall those. And I do agree with the people here that said this meta is becoming more offensive- now we have Victini, Infernape, Darmanitan, Staraptor, Honchkrow, etc. There's so many offensive threats that running stall is being less and less effective, and Blissey really only has a spot on offensive or defensive balanced teams, since it loses a ton of momentum and seismic toss really isn't going to hurt that much for more pokemon. And yeah, IMO Umbreon and Florges deserve to be higher than this thing; they may not have as much extreme bulk, but they're not setup bait.
For Blissey, I'm going A-. First of all, blissey can wall most of the special attackers in the tier. We know that. But it does have flaws- it's can easily become setup bait to a lot of physical attackers in the tier- Especially substitute ones, because they can simply sub up and if they run enough HP to live a seismic toss behind a sub, then you're in for something. The opponent basically gets up a free setup move. It requires support because most of the really hard-hitting physical attackers in the tier are able to break it, which means you have to pack more walls to wall those. And I do agree with the people here that said this meta is becoming more offensive- now we have Victini, Infernape, Darmanitan, Staraptor, Honchkrow, etc. There's so many offensive threats that running stall is being less and less effective, and Blissey really only has a spot on offensive or defensive balanced teams, since it loses a ton of momentum and seismic toss really isn't going to hurt that much for more pokemon. And yeah, IMO Umbreon and Florges deserve to be higher than this thing; they may not have as much extreme bulk, but they're not setup bait.