Im a little bit stoned and have cool ideas, yu no.
The idea is that making killing process ritual like.
The knocked out character is lying on earth. Why should his opponents make cool moves to just hit lying body? I think strikes dont must be usable on knocked characters.
The another point is that any character in fighting mode with knocked one can right klick on him, and chose "sacrifice", "cut him" or something like. This will have a cooldown about 10 seconds, make a strike to knocked that will be a wretched gore with damage affects by his str. With this option will allow to punish another people with this threats. And also killing will be not so easy as it that, but still permanent.