Hm since in most battles (at least in open fields) you will get very fast in melee, that would not be nice. They can shoot one or two times and then would be useless.
I think its okay that siege weapons make friendly fire but archers should not.
Orcs and elves should not be in the game when you want it realistic as well
However, thy could reduce the accuracy or the damage inflicted by archers, when the arrows hit targets that are in melee combat. That would be a much better way.