That is something I'd like to see more of, like the Trias fight in PS:T. Make the ending near impossible in its base form then, depending on your actions, make it easier as the support for the enemy lowers. For LS you could just remove enemies and for DS some of the enemy will change sides during the "final battle".
I want to see more of the results of my actions instead of the world being just the same no matter what I do.