Well, basically, I'll sum up a giant post I made on the official pvp forums in a thread which apparently got deleted.
Rogues are a stupidly imbalanced class in PvP. When I say imbalanced, I don't mean overpowered, I mean they've been pretty much relegated to a zerg class because of the nature of their cooldowns. Every rogue in high-rated (2200+) arena pretty much runs the same style of comps and plays more or less the same way: they sap 1 guy, then blow every cooldown they have in the first 3 minutes of a match and try to zerg down/lock down one of the others as quickly as possible. And they're really really good at it, which is a problem. For my warrior's team, a rogue is untouchable until he's out of evasions and a cloak/vanish. So, when combined with other high-pressure/control teammates, rogues are stupidly powerful in the opening of a match.
And then once they're out of cooldowns, they die hilariously fast. Faster than anyone except a dispel-spammed mage, basically. There is no middleground for them, and it's stupid, and makes them a stupid, imbalanced class as far as pvp goes.
P.S. I killed a rogue at 2400 with a 10.5k revenge, sup.