Well, Smogon just got usage stats, and along with them, released a UU tier. The top 49 (I would say 50 but Missingno snuck into the list (82)) UU pokemon are:
As time goes by, it will likely get more balanced. For now, Mew, Kyurem, Victini, Espeon, Azumaril, and Celebi are all UU. I can see All of them but Kyurem and Victini going up to OU via usage, or via banning, soon enough.Until then, however, this metagame looks extremely fun, and without as much weather (No politoed or TTar, so you are stuck with Hippopotas, abombasnow, and vulpix), and alot less centralized.
Baton pass looks fun, with Mew, Smeargle, Jolteon, ninjask, zapdos, Ambipom, and gorebyss usable. That being said, unless you are playing Adv OU, baton pass will never be game breaking consistently.
Weather, While nuetered, still is going to be huge. With Charizard, drought, and less sandstorm, Drought will be very powerful. Rain dance is usable as well, because of Raikou, Gorybess, and Kingdra. Remember that you can use Rain Dance and Swift Swim on a team, just not drizzle. Sandstorm is usable, with Pokemon like Gligar, Stoutland, Flygon, Rhyperior, and perhaps even excadrill and Gaarchomp's underevos (Gabite and whatever). With Cresselia, Ubreon, Gligar, Gastrodon, Milotic, Celebi, and, of course, chansey usable, stall looks good too. But pokemon like Arcanine, Elektross, and Ambipom are stil there to break it. Anyways, enough of my opinions.
What do you guys think of the UU BW metagame?