For custom games, I think it would be neat to have the option of playing a duel mode where two people fight and the rest of the people in the game spectate. The winner of the duel would continue playing, and the spectators take turns challenging the winner until the predetermined number of round wins is reached to end the game. If anyone has played the Star Wars Jedi Knight games, this was a game type in Jedi Outcast and Jedi Academy.

If this couldn't happen then at the very least it would be a nice quality of life improvement to allow spectators in private games so that duel mode can be played while there are more than two people in the group.