Any discussion about World of Warcraft PvP nowadays inevitably involves Arenas. With the onset of Season 4 and its new rules and requirements, Arena play is getting more intense than ever. Of course, as the competition heats up, the cries of an imbalanced contest grow louder than ever. Blizzard seems to be aware of the issues and have taken some steps in the development of the Wrath of the Lich King to address class and spec viability.
During the panel on "PvP Game Systems", however, lead designers Tom Chilton and Corey Stockton devoted most of their Arena discussion to the new maps rather than the hairy, and probably inconclusive, issue of class balance and representation. The new Arena maps follow Blizzard's philosophy of keeping things simple yet have room for innovation; having dynamic points of interest; having conceptually different starting areas; and leave allowance to make adjustments during development.