This is pretty close to what I mean! However, I want the players to have full access to the editor, just only building their own world - while still having the client to log into the hub world and make friends with everyone else. So they would still have access to making quests, items and so on, with the only provided resources being the graphics. Definitely would need a system to create, edit, share maps, ideally through the hub world AKA the client.exe.
Okay so I don't think I'll do this but I was just wondering because it feels like it would create a very unique community.