Sounds nice that you can play with 2, 3, 4, with IA, etc. in MP It would come in handy if someone has to leave or the net goes down here, as usual.
That kind of cool hybrid system would allow some pretty crazy stunts in Mp: Taunt the guys with one player, flank with the other and then a zero strike together if we are side by side.
Also it seems darkvision became a very important feature if you are playing a rogue or some sneaky character, for players and enemies alike.