Hello there mate.
it really depends, if you go for arena and you go dual dps its good enough.
the problem is that you can only do anything when you cd´s are rdy. if the person survives your first cd´s burst, you have pretty much lost the fight.
A good ele shammy and a combat rogue can abselutely pwn if you play it right
with 2 slow weps. but again, if he survives you have to wait 2 mins or you lose.
Also that one with the elemental shaman, because, I really want to do some Arena, but in arenas i would start up as a combat, after i will go multilate (assosiation/Sublety) because I've head sooooo much good of a multilate rogue
But what's good for a rogue to do arena's with?
Honestly i dont know so much about rogue's yet.. this is my first rogue, im used to play Druid :-X
So if someone can tell me a bit about rotation's in BG and Arena, it would be nice ;D