Deoxys-A rising to B rank.
As pretty much THE person who has hyped up Deo-a all throughout BW2, I have to say - it really kind of isn't too good. Slapping a Life Orb on it makes it die to every spread move stronger then Cress's Icy Wind (which still does close to 50% IIRC), it's incredibly predictable, only has single target attacks, and for PURE POWER, you can always run titans like Kyurem-B or Mega Medicham who have actually existant bulk stats. It really doesn't help this is the meta of priority, and if your follow me user is dead or not on the field deo-a is superbly boned. It also cannot switch into ANYTHING, so bringing it out can be an enormous pain.
Abomasnow falling to C rank.
I'm of a mixed bag on this one. Almost everything with anything resembling offense in the metagame hits President Obamasnow for SE without even trying. Ice/grass is so incredibly awful as a defensive typing, even with 90/105/105 defenses. It REALLY needs support, and a lot of it - if it isn't being run with trick room or some other form of damage migation, it's basically a sitting duck at an incredibly crappy base 30 speed. It cannot, in its best form, run a damage boosting item, and its best attacking move was nerfed to 110 BP. Hail was nerfed to practically only last 5 turns (you aren't running a icy rock with this thing). Its awful base offenses in its non-mega form really hurts Scarf sets. It also did absolutely nothing for two terms, and has allowed Team Flare to run unchecked in spying on our communications.
And yet...
It still summons Hail. It still has a spammable 110 BP STAB spread move with a 20% chance of freezing SOMETHING per turn. It still enables the rest of its team to spam that 110 BP spread move. Hail is still a painful damage over time effect. It still has 90/105/105 defenses. And it can still (reasonably well) run mixed offenses.
Still, though, the Hail and Blizzard nerfs REALLY hurt. Let it fall, I say.
Edit: Also, the meta poops on it.
Musharna falling to C rank.
Honestly, if Cress didn't learn Levitate, I'd be totally fine with this being B rank. As is, B rank is bloated, and mini-cress is still mini-cress. Supporting.
Shaymin-Sky rising to A rank.
This thing is so freaking clutch it's unreal. Flinch can BS your way to victory even in your darkest hour, grass/flying is great coverage, and 127 speed is fantastic for picking off mons, and outspeeds almost all of the unboosted tier. Supporting this.
Jolteon falling to D rank.
Yes please let this thing die.
Gallade falling to C rank.
shamelessly stealing reasoning said:
Yes. TR settler that hits hard but there are harder hitters, and it has good special bulk but there are bulkier Pokemon and is compromised by bad physical bulk. Whilst it can hit hard and have good special bulk together, there are other Pokemon that are better with that combination in TR, and more importantly, you're better off using bulkier settlers like Cress and more offensive TR sweepers like Conkledurr and Heatran. It's typing is also bad defensively and gives it few switch-in opportunities. It's hard to justify its use. It's movepool is great though, and it has niche options like being a Fighting-type with Will-O-Wisp, and it gets Heal Pulse which has been buffed so that if your ally faints before you use it, you no longer heal the opponent. C-rank.
Medicham being added to B rank.
This thing is actually really damn good. Having messed aound with it, it's pretty good at what it does - breaking shit. Bulk lets it live some stuff too. Support.
Porygon 2 being added to C rank.
No comment. Haven't seen this, ever, and have never used it.