I see what you mean but you already have the option to do exactly what you want to do and I don't want restrictions that prevent me from trying something else.
I would rather have the option to end with a big boom or not. I would like the option to snipe enemies from a distance sometimes. I would like to set traps with barrels or other features of the environment. I would like to set up ambushes. I would like to win a fight 100 different ways.
That is what gives the game replay value once you know the story inside and out.