i agree with Petrie911 for the Tier list calculation. Does UU follow this rule too?
Anyways, my short attempt at a little status report ^^. For OU only... ==
Let's start with the top.
Heatran. He's still up there. After the Mence ban, Scizor was less used as a revenge killer, but it is still useful. Heatran is still there with the 4x resistance against bullet punch and fire which kills Scizor. Scizor is still out there with it's OMG STAB priority Technician Bullet Punch that virtually kills everything that doesn't resist it. It has less use with Salamence gone, but nonetheless still a good pokemon.
Gengar has rised up and high! With Salamence gone, it's a little harder to explit it's defenses, although Scizor still cripples it with Bullet Punch... unless Gengar sets up a Substitute! The main set that gets praised now is SubSplit Gengar, which with Gengar's low HP, can cripple walls like Blissey. His Special attack paired with speed is also certainly quite devastating.
Dragonite made a big jump! Everyone knows why. He's now the official dragon of OU with Salamence gone... but he still has to deal with Flygon and Kingdra, which of Flygon is more of a threat, not only having Spikes immunity and is also resistant to Stealth Rock!
Blissey is now not used much. Why? With Heatran at top, the Special Wall should be more used! With other Special attackers up there like Starmie, Rotom-A, Gengar, and- There's one of the problems! Subsplit Gengar counters Blissey horribly. Don't forget other awesome sweepers; Gyarados, Tyranitar, Scizor, etc. are physically strong, and Blissey fears them.
Vaporeon had had quite a bit of an uprise to counter Heatran! Also benefited from the Salamence ban, Vaporeon is quite a dedicated wall; With High HP and Special Defense, it is a fully rounded wall. What? You say that it's defense isn't good enough? It may be low, but only part of the Physical Sweepers can Abuse it. First of all, Acid armor strengthens it and makes it stronger. Scizor cannot hit it with the most powerful Bullet Punch, so it must resort to other weaker moves. Gyarados cannot hit hard with STAB Waterfall; and Bounce leaves Vapereon a free turn to set up. With it's high Special Defense, it can fend off one or two Thunderbolts or Grass Knots/Leaf Storms.
The most used Rotom form, H, has fallen below Jolteon! Although the causes aren't that clear, Jolteon sweeps better with Higher speed, although it doesn't get bonuses from Shadow Ball. Or, Jolteon can Baton Pass, one thing that Rotom doesn't do.
How is Suicune still sitting down there? It can both sweep and defend. It's typing is also very Beneficial. It should rise up, especially with Heatran dominating.
Rotom - W also had quite a big jump! Was it because Heatran is at top of OU?
Roserade also had some improvements. First of all, it has STABed Grass attacks, which deal with Swampert. It also has Sleep Powder, which is very effecient. Spikes support is also very useful.
Why isn't Shaymin up there yet? Grass is quite a useful type in OU, and Seed Flare performs extra well as Shaymin's STAB attack, also having a chance to cripple Blissey by lowering the Defenses.
According to calculations, Heracross is moving down to UU! It'll probably get BLed anyways so it doesn't have such a big impact.
Report Finish!
I'm sure there's better stat geeks than me...