How about moding a different hit detection box for the head with a huge damage multiplier to make headshots deadly for normal foes? Of course bosses and dragons would have a smaller multiplier so you wouldn't be able to one-hit-kill them as easily.
I thought of this because I find it very annoying fighting bandits with arrows stuck to their faces. Big immersion breaking.
I don't know if it's possible but if it is I'm certan it will require the CK.