Many people have had this idea before, so it is just the execution that matters.
If I'm correct, this is Little Big Planet meets MMORPGs on player run servers. This idea generally always starts with,"Imagine if everyone could make their own levels and people could go from server to server with the same character." But then the realization that hackers could do what they want with your player data when you entered the server makes a game designer then go,"Okay, so let everyone design the rules on their own server then since hackers will do it if we don't". The cool part is if you allow monetization of player made Objects which sell in a global store across all servers. The owner of the object created and the game company would split revenue. There's some details about how things could be hacked to spawn free items, but a little thought could quell the hackers on this front.
The coolest part is that you could have games which are like Skyrim, but there would be live gamemaster(s) there. They could then have you interact with NPCs with live dialogue or do things a computer game alone wouldn't be able to reason. People could be in serious demand of a game where they are playing with a live game master because there might be continual end game after being capped with equipment.
Between charging for objects people made in Blender and uploaded to the game development team to be put on the market, and people charging for monthly access to their server, the creative minds could make enough for rent on this game. And once creative minds developing new worlds are making revenue, there's no stopping how in depth the games get. This in turn draws more players and developers in too.
For the past year I've been saying the future of video games is video games with quality map makers like Little Big Planet, but sharing revenue with the creators of the new content.