If two players kill an Orc named Ûgak the Black-Blade, to whom does Ûgak swear revenge? Does he cheat death against Player A or Player B? The system cannot split a grudge.
This system tracks thousands of variables for individual Orcs. Syncing these across two PCs without crashing the game state is a monumental technical hurdle. middle-earth shadow of war multiplayer co-op mod
"Shadow of War: Fellowship of the Ring"