If burst is the new king, Paladin's are the queen. Their anti-burst bubble's make them the best class to counter burst (especially melee).
Note: It is way too early in the season to truly see where the classes are going to end up. I'm just bringing the facts as they are written. Just take the facts with a grain of salt; it is too early to make great judgments concerning classes.
In the top 100 in 2's, there are 57 paladins (28.5% representation, half the teams had at least one paladin)!
There are in fact a few Hunter's in the top 100 (12 at the moment, 6% representation). Almost all of them are 50/21, which is getting a severe nerf come next patch.
The rest of the classes in the top 100:
37 Death Knights (18.5%)
36 Mages (18%)
34 Rogues (17%)
8 Druids (4%)
6 Priests (3%)
5 Shamans (2.5%)
4 Warriors (2%)
1 Warlock (0.5%)
From the data, right now, in the first week, it looks like Paladins, Death Knights, Mages & Rogues are doing very well in some combo's in 2's. Every other class has much less representation at the moment.
Now I also know that on my server Death Knights and Paladins are the most played class at 80, representing 26% of the player base at 80. If this is true for most servers, than Paladins and Death Knights should do above average just because of their higher player representation (opposite goes for lower played classes).
My 2's experience this week (Hunter/Rogue):
We can blow up half the teams real fast and I can kite around pillars (except in the terrible Ring of Valor arena). We have extreme trouble with Paladin and Death Knight teams. This is unfortunate because we play these 2 classes in half of our games.
My 3's experience this week (Hunter/Rogue/Death Knight):
I die so fast, it hurts so bad. Please oh god, the pain... Cannot wait for new Deterrence... anything to stop the murdering of my poor, poor Hunter... It did not help that almost every game was in the Ring of Valor, which was suppose to help Hunters, but in my experience, it is my worst arena by far since Hunters have terrible defensive abilities.