Perhaps at a certain place [Mt. Hildar?] you could meet up with 2-4 friends and do co-op missions. Not certain how this would all sort out, but it'd be cool to travel with non-AI or characters YOU control.
Also, for PvP, how about getting the audience involved? Booing, Cheering, and throwing rocks that do a point of damage at the fighter you don't like.
One bread ahead of the bread. Two bread; too much bread.