In icecold wow these doesn't matter anymore. Best gear class pwns all :(
But in retail it was like
2v2 Arena
Pala & Priest
VS
Druid & Rogue
The druid and rogue can play alot better but priest is too good for healing :)
A little story
In arena with my Leeroyz druid i fighted with my rogue against a MAGE / WLOCK team and we got the lock down pretty fast but then was a mage left. He did froze us with his pet and teleport away. Then he did cold us with the freeze spell. It took about 5 minutes to get this mage down :D
Video sent to Blizzard and received an ansver where they told they will nerf Mages :(