That's actually pretty nice, I never thought of it much but I would love a couple of non-lethal takedown moves.
I tried to do the kidney punch as often as possible when freeroaming the rooftops in previous games. For some reason randomly killing innocent rooftop guards who are just doing their daily job felt wrong and against everything the game and the main character try to convey.
Worst moment in the entire franchise regarding the random killing of soldiers: the part in the catacombs in ACII, where the two guards find a piece of gold. This one guy says "O boy I can't wait to show this to my wife tonight, she is going to be so happy". Enter Ezio Auditore da Manslaughterenze who casually stabs the guy in the throat and leaves him bleeding out in some godforsaken place never to be found again.