There's an ability that let's you backstab with a weapon other than a dagger. Never tried it but it sounds that it would be good. My co-op partner and I did the rogue thing and she ultimately turned into a ranger too with some lockpicking.
The warrior for me is a beast if spec'ed right with the right gear (gear is everything for the warrior it seems). I'm doing 60-70 damage against level 5 baddies and much more to lower ones.
