'Gaming' the lobby
I suggest anonymizing the players in a lobby until the first round has started. It's common to see people entering and leaving a lobby repeatedly because they don't want to play against high ranks or certain users. This has been an issue for a while, but I think with the release of the competitive series it's more important now. In order to reach the top of the series leaderboard you basically have to win 10/10 games for each game mode, and that's easier to do when you can just exit the lobby until you get a favorable group of opponents.