I'm not sure if there was a suggestion thread for this made, I'm pretty sure there would be one by now, but my suggestion is:
Allow random people to join your game again.
I personally was very disappointed when this option was removed because I liked having people join my game to look around my world, it's not very fun just having your same old friends join over and over, it brought something more to the table to have randoms admire what you work on.
I think there's enough protection now to allow this to work: Trust Players option, having it set to only friends joining or friend of friends, invite only games. There's even a kick function. Not to mention when a person is kicked once, they can't rejoin unless the game is restarted.
People may have complained before but I find it unfair to those that enjoyed letting people browse through their worlds just because people don't know what the kick function is or know how to use the correct protection to guard their worlds.