This is an unnecessary command imo. I mean, If you don't want to type a few characters more than you'd like with /leave, then as everyone is saying you can type /hub really quickly regardless of the game you're in. Instead of adding this feature, you can activate the auto-mode to avoid being constantly typing a command though. Also, nowadays, there's no need to type /leave or /hub since you have a button when you finish a game with which you can leave a game.
So I'll have to disagree with this one since it's totally unnecessary.