An automatic thread deletion. 6 months old with no activity, unless stickied, gets deleted.
Maybe limited access to brand new users...since we've had so many issues with new people trolling and starting internet wars for no reason, throwing out neg-rep like old toys, it's starting to get a little out of hand. (Or so it seems.) Maybe have a 30 day period where they have limited access?
The rep system. If it's starting to get out of hand, I have another idea. On k-1fans.com, a forum I still frequent, they have their "rep" status change by how many posts they have. There's no rep thrown between users, but it's kind of like an award for being active. Then, anyone that would be a douche just got banned. Of course, this would be a big change, and would require more reporting from the underlings and more work for the mods, but it's an idea.