Apparently I can't outright request mods. Whoops. So, lets try this again; I think an interesting feature to add would be designated towns/protected areas. I'm not sure exactly how this would work as far as designating borders (the city I'm building is a bit of an odd shape, and it's also practically on top of my friend's fishing village), but basically, within the borders, players (not including the host and/or mayor) cannot build, destroy, mine, etc. unless they become a citizen of said town, and would also require the mayor's permission (my city, for example, would not allow residents to build their own structures, or mine, but would allow them to (somehow) rent a room at the inn or buy a house). Also within the borders, no mob of any kind could spawn normally and creepers, if lead into the town, would despawn instead of exploding. Other hostile mobs would not deal damage. The host would have overall authority of who can set up a town, and would be the one to draw/alter it's borders. Any structures outside of a town's border would remain "fair game", so to speak.