I'm sure you're smart enough to make changes that will boost the level of civility, and not reduce it. At the moment, the biggest reason not to zing someone with a cheap shot comment is the fact that you will soon find a negative number attached to the comment (how humiliating!). I suppose you could hide the points and completely hide comments that wind up with negative points (and, to have the discussion flow make sense, you'd have to also hide the responses to that comment). I'm sure you'll iterate, and find out what works best. Good luck, and thanks for caring enough to try to improve things around here.