Vhiari, keeper of the Armory stats, has updated once again, this time taking a look at Arena performance across all three rankings and all of the classes contained within. The 2v2 comparison (showing Arena rankings, across the bottom, with the percentage of players in each class at that ranking) tells the overall story: Mages are seeing major gains in the Arena, as are Rogues, which Vhiari speculates may be at the cost of Warlocks (who took a small tumble). And just as last time, Hunters continue to struggle in all three brackets -- 5v5 has the same situation as above, but in less extreme amounts.
Of course, these are stats, and what these stats actually mean is up to you (and more importantly, up to Blizzard -- this is just a sign of who's getting which rankings at which levels, and this could be the result of many different things, so there's no reason to expect buffs or nerfs based on just this information). Still, it's a pretty clear look at just who's winning out there, for whatever reason -- the stats say Mages have done well the past few months, while Hunters continue to struggle inside the Arenas.