"Join when there is a spot" button
Introduce an option that lets you join a server when there is an opening.
Sometimes when tournaments are held the place can get packed pretty fast and you have to keep on trying to reconnect waiting for a spot to vacate.
With a greater player-base this might become a recurring problem so this would be a measure against it.
I remember Counter-Strike had a similar option on steam, so that's where this idea stemmed from.