My wife and I finished the original D:OS in lone wolf hard mode with a mage and a rogue. Once you get the rogue fully up to speed and with a good dagger, they are insanely powerful in both single-target damage and crowd control. I recommend a hybrid rogue/caster with some points in air and earth. The air spell that leaves you behind enemies for a backstab is a great move.
I always start out as an archer-type when playing a rogue, because they have trouble in the first realm (no points in bows since you will be switching to daggers later).
