I've been fond of the idea of a suspend-points system, where users can complain about other users, and after a certian number of complaints, the user is banned from LJ's servers. (Sure it could be abused but for the drama to die, it'd be worth it. ;_;)
I also think crossposting is spam, even if it's vaguely related to the community, so anyone who crossposts to more than 3 communities at a time should be suspended for violating LJ's TOS.
Anti, rating, and elite communities should all die. And multiple communities should all be merged together, having the excess deleted, maybe a vote system to determine the moderator(s) of the communities. It pisses me off to see certian communities dead and and their counterparts active but run by jackasses.
I could probably come up with a few dozen, but I know most of mine will trigger flamage and "OMGFREEINTERNETWTF"-age. Ahwell.