I understand the problems you are trying to solve are serious, but your solution seems to me very much like nationalization / expropriation. I am not sure I want to punish bad behavior by seizing the bad actors' property (SP). I just want them to stop acting badly.

From this point of view it might be better to seize their voting power only. This way they will be unable to do more harm without expropriating their SP. If they don't want to improve their behavior, they can power down & sell. On the other hand if they do want to improve their behavior, they can power down & power up with a new account (still a form of punishment because of the unrealized possible profit).

We as a community don't want to look like thieves, we just want to make bad behavior uneconomic. Also we wanna be open to everybody and offer an opportunity for bad actors to improve. If we seize their SP after 1 incident, they don't have the opportunity to improve and their only option is to start complaining, shouting on every corner how bad Steem is..