> "IMHO, the most ideal strike a human can give without injuring themselves would be from the shin or heel. If you look at animals that don't have sharp teeth or claws, often they'll use their hind legs in a kicking motion to provide the most powerful hit, while moving their sensitive head/neck/chest away from the target. A few human groups developed fighting styles this way, but for millenia we've still been fighting standing up. I can only assume this is because we got so used to being bipedal that we adapted our fighting to it."
Most fights between people end up on the ground very quickly. Optimizing for full-stroke punches and kicks effectively forces your strategy to be "debilitate the other guy before he can get inside and close". The difference between humans and the non-toothed/clawed animals you mention is that humans have arms and hands that can defend against the slower knockout blows you mention.
Wrestling is a more accurate sports approximation for how humans "naturally" fight (assuming 1-on-1).