Relmstein has an interesting commentary up about crowd control in World of Warcraft, and how balancing it is imperative to get PvP done right. It used to be that fear was the main problem, but now that fear has been nerfed and balanced with so many other abilities, it's just crowd control in general that has become the main issue. Instead of Warlocks and Mages ruling the roost with Fear and Polymorph, almost every class has picked up their own little methods of stopping other players in their tracks momentarily.
And thus, says Relmstein, the quicker abilities are becoming more powerful. Blind and Cyclone are the two main abilities he mentions, and both are extremely powerful in that they can be used by Rogues and Druids in conjunction with their escape abilities. And on the other side of the equation, Relmstein says that burst damage is king-- doing serious damage in between those moments where crowd control can stop you is critical. And that's why Warriors (and to an extent, he says, Hunters) are doing so well in the Arenas. When you can break out a ton of damage and debuffs during someone else's global cooldown, you're going to go a long way towards winning.
And it'll be interesting to see where this all goes in the future. With the recent changes to spell haste and the curving up of gear in the expansion, things are just going to get faster and faster-- players are going to be able to push out damage quicker and quicker, and crowd control will be more and more powerful.