It seems like Demon Hunters, with Reverse Magic and Darkness (amplified by PvP's Cover of Darkness) make for a crazy team. With 8-10 DH, you could rotate Reverse Magic every 2 seconds or so... That would fix all your root problems (Frost Nova and the Druid root)!

Anyone have any idea of how fast the PvP leveling will work without doing BGs and/or arenas?