Yeah, I'm aware that Pratchett is on record saying that he didn't think it could work. But man... we can dream. I think it would make one damn awesome mmorpg.
I think, for instance, if I was playing some big boss battle and then all of a sudden Rincewind runs across the screen screaming, "OhshitohshitohshitI'mgonnadie!" followed by the luggage.... Yeah I think that would make my life complete.
So am I totally full of it? Do you think the world is incompatible? I got to admit, just thinking about it makes me smile a little.