Forretress: Having Spikes and Spin together is more than just a simple teambuilding shortcut. All the hard counters for Excadrill (assorted bulky ghosts) and Ferrothorn (spinners with resists or Xatu) are insufficient against Forry as the combination of these two important support moves forces the opponent to pick their poison. Either they block the spin (which he isn't that bad at doing as he can Toxic the ghosts that aren't major Spikes fodder) at the cost of extra layers going up as they switch or they cut off the Spikes and watch all of theirs disappear.
Kabutops: Kyogre is THE most used Pokemon in Ubers and has been since forever. How can needing the support of the king of Ubers reduce the viability of anything? (Torna-T was S rank in OU despite the fact rain doesn't have such a powerful abuser) His base attack is far from low as he hits harder than EKiller and has a powerful coverage options that still outspeed everything not named ScarfTerrak (who beats EKiller as well) and Ray.
Bisharp: Faster priority doesn't do much when he resists every usable priority in Ubers and can still Night Slash. It may not be switching around willy-nilly (EKiller can't either) but he still has no difficulty getting a boost. (and still has utility without SD thanks to Sucker Punch) Again, he takes prediction to sweep but less to setup and seeing how dangerous he is and difficult to reliably stop he definitely deserves a B rank.
Frosslass: Yeah, that's true C rank works then.
Mamoswine: (Yeah, I couldn't remember the set he used just what he could do. That's why I included both LO and CB calcs)
So outside of bulky Arceus (every Pokemon has its fair share of checks/counters in Ubers) just about nothing can safely switch into Mamoswine while he is going to blow holes into just about every Stall team in Ubers. Again, he has his checks/counters but that shouldn't stop him from being a B rank mon. (especially when Ice Shard means he isn't just wall breaking)
Omastar: The difference between Cloyster and Omastar is that Cloyster is dead weight until it sets up on the choice locked Ice Beam. Under Rain Omastar is faster than Mewtwo and his rain boosted Hydro Pump is packing 2,7 times the power of his Psystrike, which largely makes up for the mere 1,12 times extra umph behind Mewtwo's SpAtk. (Not trying to say Omastar is better, just that his "weak" special attack is made up for by his ridiculously strong attack by comparing it to a widely recognized powerhouse) Pair that with good SE coverage and Omastar is posing a significant initial threat that risks doubling if you attempt to shelter one of your key members from it.
Reshiram: Reshiram doesn't rely on Sun at all. He has powerful dragon attacks backed by 150 SpAtk. Not to mention Blue Flare is still going to roast steels like Ferrothorn that tend to use most dragons as setup fodder under Rain. The reason it's silly to use Reshiram outside of anything but a Sun team (Well, he works fine on Sand as he can try to predict steel switch-ins easier knowing that no matter what Blue Flare is going to bite something hard) is that in any other situation you are probably better off with something like Palkia or Kyurem since Blue Flare is the defining feature behind Reshiram. So yes it does face competition from these dragons, however it isn't outclassed by them nor is it a weak choice in and of itself so sticking it two tiers below them amongst the dismissable Kyurem-B (who is outclassed by Zek and suffers from a very poor movepool that makes him a mediocre pick anyways) I feel is a mistake.
[01:47:47] <+Limi> gamefreak has confirmed the rumour
[01:47:53] <+Limi> that mewtwo now has a tumor
[01:47:59] <+Limi> but please man, chill out
[01:48:03] <+Limi> you don't need to pout
[01:48:08] <+Limi> just take it all in good humour!
Originally Posted by Fat trickroom
Blizzard is for the whole Dragon Slayer thing, it OHKOes almost any Dragon in the tier save Kyurem, Giratina, Dialga, Palkia, Reshiram, Zekrom, Latios, Latias and Giratina-O.