This game has been going on for many years and worlds, so what about partial resets to retain more players? Basically you lose everything except your character and his stats/skills.
Currently the sheer lack of any sort of permanence is what kills the game for me at least, and i'm sure that's the same as the majority who quit.
I would suggest old character should have to wait a week before joining the new world to prevent wholesale slaughter, so people can get defenses up before then.