Max. boot rate, min. games played, blacklist: these are all indirect ways of getting good players in your game. One of two things could be done:
1. Have a min. winning % for the type of game proposed. Eg: I create a 3 v 3. I make the min. winning % to join 55%. Only players who meet this requirement can join.
2. Players are given a rating (like pogo.com games or warlight's ladder). I beat a good opponent/team, my rating goes up more than if i beat a bad opponent/team. Vice versa for losses. Then, a minimum rating could be used to limit people who join. Eg: good 1 v 1 players on the ladder seem to be above 1500 or 1600. Use those numbers as minimums to join.