I came up with this idea while trying to get people to join a custom game which required more than 2 people. My idea is to have a playlist in which a player is randomly chosen from the party to be the leader and choose their own custom game type(infection,slayer,etc.) and map. Everyone would play in that game. After each game that you are not chosen to be the party leader, your chances of being chosen grow. You could also have the option to not be the leader, if you just want to play on some other peoples maps.
Sorry if this is hard to understand/bad grammar
Thanks