This idea(s) may have already been suggested.
Private and passworded matches. It's relly bugging me when I wish to play with friends that I have to kick everybody else just to let them play. I don't think it's fair that these people join and get kicked just find there's no game with a spot left etc.
Private games simply being invite or join-through-social-list only. (Also an invite to game would be nice but with some sort of filter to stop spammers.)
Passworded games, well thats self explanatory.
I think that's all for now haha.
Cheers!