Allow all maps, but sort servers with amateur/broken maps/rotations into a hidden list. They'll still be in contact with the masterserver but the masterserver need not publicly condone poor gameplay. Players can still connect manually. Everyone gets to play whatever they want to play and the devs can maintain the gameplay they desire for their game.
Maybe clients could choose to display this list in a separate menu. Maybe.
Maybe clients could choose to display this list in a separate menu. Maybe.