What about an option in the map selection screen that allows for choosing a map at random from the ones available to play on?
Perhaps just a button of a dice (the same that you get when creating a team) that changes the selected map randomly (it could include the autogenerator as option to change to).
This is useful when you have a lot of maps and can't decide on one. Or you just played every one and can't think of a favorite for the moment. Or sometimes your friends just want the computer to randomly pick one, instead of you who might be biased.