I don't know how feasible it would be to have the game essentially double its workload to show each character on a different screen, but support for a second monitor would be nice (if it wouldn't take a lot of work). I think the map / journal would be better on a secondary screen; not sure if having the inventory always open would be more convenient if there would be extra mouse movement required to get to it (compared to using a hotkey). It wouldn't be mandatory, anyway, so people could presumably configure a second screen as they wanted, if implemented.
