I think morale shouldn't be a simple number... Think about it this way, if the soliders close friend gets killed he or she could get pissed (and fight berserk) or get depressed and assume a fetal position...
I do not actually want a sims-like soap opera but the game should promote the use of "same soldiers" who work more efficiently with each other. Even a group of pro soldiers wont work well together if they are going to their first mission. Even pro soldiers can loose their cool...