This metagame is highly revolved around revenge killing and the infamous multiple dragon strategy to break down steels. Usually having just the right Scarfer, usually Skymin, Latios, or Garchomp, can win the game for you. There are also some surprise scarfers like Mence and Manaphy that can turn the tables right away.
The individual suspects:
Deoxys-S: agreeing that this one has a high chance of being uber. The Dual Screen sets, as well as the spiker sets that dominate Ubers are coming down and ruining lead set ups and setting the tempo of the match. The cleaner Life Orb sets have an easy time getting through once Scizor, who is usually overwhelmed by Draco Meteors and Outrages, is gone.
Skymin: Scarf set has definitely become more popular than when Platinum first came out, being one of the few that can outrun Deoxys without a +Speed nature. Skymin is tasked with revenging other scarfers (Modest Scarf still beats Lati@s/Gengar, who sit at 525 speed with a scarf), Garchomp, Manaphy, and other Scarfless Skymin. People found that the Life Orb Sub set was too frail, so it has been dropping in usage.
Garchomp: not what it used to be pre-Platinum. Goes a long way in showing how amazing (and important) CB Scizor is, who can punch away half of Chomp's health. Yachechomp isn't great now with all the scarf dragons (people have been using Haban Berry what the fuck?), CB is insane, and Scarf is the most popular.
Latias: only a few seen. Not having much of an impact at all. I thought it would be able to take on LO Deoxys, but apparently it can't, getting 2HKO'd by Ice Beam after rocks, though mine only has 176 HP EVs. Outdone by big brother.
Latios: this one is a huge problem, simply because of Specs Meteor. Serves a great role in paving the way for other dragons/Skymin/Deoxys, blasting through steels. Blissey usage shouldn't be discouraged because of the highly offensive game. Most of the suspects are specially based, which by the way may say quite a bit about the community, throwing up a red flag for uber when forced to use Blissey. It can come in on the Latis and Scarf Skymin rather easily and slow down the offense a bit.
Manaphy: have not faced one at all.
I've had great success with Resttalk Gyarados, who seems like it can't find sufficient time to set up with all the heavy offense. From what has happened, setting up is very easy, using choice locked pokemon on EQ and weakened Draco Meteors. Teams find after a couple of DD's that they can't KO it easily.
Haven't seen any Lucario/Infernape/Rotom/Zapdos/other OU staples.