Dang, I really do hope they manage to patch this into the game, it's what I loved about dungeon siege 1 as well, being able to pretty much do your own thing as well whilst the other guys in your party would be out doing the game at points and you could even set a teleport spell to get your team mate that was in the main town to your location quickly, I suppose 2 people sharing a screen would be...decent, just 4 players and it would be like when I was playing Cod black ops and your doing dead ops arcade with 4 people, it made it so much more stupidly harder and frustrating then it should of been, like dying because you coulden't move out of the screen area or getting killed from behind where an enemy is, yet we couldn't see it due to the horrible camera.
I do hope this gets taken into consideration, I dare say this may even effect there sales on the game if other people discover about this, good luck to the devs!