Originally Posted by Fat NATdude
Cofagrigus, however, should be S ranked. He walls a good number of Pokemon like heracross and can set-up on even more. Trick room/NP is extremely deadly. It alone can sweep teams lacking toxic or a healthy special wall. His supportive set is great too. Crippling physical attackers and walls with will-o-wisp and healing off damage with pain split. An S rank poke for sure.
Some other Pokemon that should shift tiers:
Dynamic punch hits like a truck and the confusion hax can lead to a huge disadvantage.
CB and life orb sets can wreck teams that lack a good check to weavile. Pursuit kills all the ghosts in the tiers and ice shard is a great overall stab move. Low kick, night slash, and ice punch are all great moves to add to weavile's arsenal. If unprepared and with hazards down, weavile can take down whole teams.
Finally, moving colbalion and empoleon to A might be a good idea. Both of them hit like a truck and can take hits in return.
Agree with Rotom, Crobat, and Frosslass, disagree with everything else. That's why I cut out certain sections of the quote, in case anyone was wondering.
Cofag isn't S, it requires support to work perfectly and isn't able to take on entire teams that lack a surefire counter (look at the other S ranks, if you're not completely prepared for them, you're going to lose). The fact that it's a wall/bulky attacker means that it's going to be worn down by anything faster, and if you're really going to Calm Mind + Trick Room, it's unlikely you'll find enough time to set up for a real dominating sweep without some really awesome support from a team. It still loses to Yanmega, Sharpedo, Shaymin, Heracross w/Night Slash, Weavile, SubCM Raikou, 80% of Kingdra variants, Snorlax, and various other thingies. Yes, it's really good, but it's not QUITE good enough to be S.
Machamp is slow. It's also not bulky enough to make up for it being slow. Yes, DynamicPunch hits like a truck and confusion is fun, but it requires switching in on something that can't do anything to it on top of the opponent not having a ghost. Plus, if your opponent IS switching, they're probably switching to a counter, and you really don't want to hedge your bets on that 50% of if that Brave Bird/Air Slash/Extrasensory/etc. will actually land.
Weavile simply doesn't have the movepool or bulk to be good enough. Yes, its base stats are amazing and it's a great choice for a team that needs a speedy attacker to clean up. No, it can't hit as hard as you'd think. If you really want to be doing some damage, you've got to have SD, and 95% of the time that requires sacrificing something/a well timed u-turn, not to mention your opponent having something out that can't hurt Weavile (mons that can't hurt Weavile being few and far between).
Also, Cobalion and Empoleon also suffer from not quite as good as you think disorder. Yeah, Cobalion is decent at doing a lot of things. But Cobalion isn't really good at anything in particular- being weak to fighting, fire, and ground just does not help it be a wall, and base 90 attack stats don't help it be an attacker. Empoleon is too slow and exists in a tier full of fighting types that can OHKO it. It requires careful switching, careful playing, and good support from a team to really pose a large threat. I love Empoleon, I haven't yet built a very successful team without it, but it's not quite good enough to be A.
Also, uh, your last 3 suggestions all lose to Heracross and Mienshao. Losing to both Heracross and Mienshao is not a good thing ever.