I'm a complete newb, (well, I was Elite in the 80's), but surely the balancing mechanic is simple? Just allow a player to put a bounty on another commander if their ship is destroyed? That way, in forced PvP, overly aggressive players become more worthwhile for BH's to take out. Piracy wouldn't be affected, as you could still take out drives and suchlike to get people to drop cargo, yet willful violence would be punished. Whether it's one huge bounty of a couple of million from one rich trader, or cumulative from smaller ones, BH gets a boost and anti-social players get a comeback for their actions.