In raids, more times than not (with some exceptions) equal geared demo/necro out dps any rogue and in pvp they do the same. They have equal cc (better cc than barb) and way dps with it even being at a range. So what are the use of rogues/hox? (my guess, rogues are just more fun to play) but sometimes demo and necros in pvp ruin the game.
My thought is that ppl can make their own pvp game rooms where they can decide what classes they want to fight against. (I bet you will see a lot of no necro/demo/conq)