Oh and with regards to the point of the game is to KO, I think in a close game, it would encourage going for the KO rather than turtling or running away because you wouldn't want to lose due to a few bonus points that your opponent had from damage inflicted.

In short, say you've KO'd a Valkyrie vs. your opponent who has KO'd your Asgardian Warrior, so you're ahead by 1 point and time is running out, it's not viable anymore to run around the map because your opponent may jump ahead of you in points when damage points are factored in at the end. So, you go ahead and try for as much to KO as you can.

One more thing that came to mind that wasn't mentioned are the Mystics. They certainly become just a little more valuable if bonus points for click damage inflicted on the living are awarded.