It does need refinement, but I think this system could go a long way toward the holy grail of making roleplay a rewarding behavior. Maybe some sort of "team experience" could be introduced, so that you could only grind yourself so far, and then you'd have to actually get a job and do something specific in a team. Sure, I'm a competent rogue, but that won't impress anyone unless I'm a worthwhile team member.

The teaming has to somehow benefit every member of the team. I remember Phantasy Star Online. In that game, the enemies don't give a lot of XP, and so the only real way to raise levels is to always be pushing yourself to fight the toughest, meanest bad guys around. Alone, you'd need a lot of time to get through levels to find tough baddies. In a team, you could be at a much higher difficulty than your character could handle, and so you'd profit more. Playing that game offline is miserable, but online, with a decent team of complementary characters, you can really get the job done.

PSO is perhaps the purest grindfest in the universe, but that little feature adds a sense of community and interest to the game.

Guild Wars has tried to address this problem as well. The entire system is built around team/party play. Everyone specializes, so no one is able to survive by themselves very well because they lack certain skills that others can provide. When a team works together and compliments each other, the group can be truely formidable and go places they could never go alone. Since it is impossible not to specialize (at least to some degree), finding complimentary party members (or at least hiring NPC's) is a must.