Avoiding disliked players
If you are not last to join a game, you are unable to avoid players you dislike (e.g. kingmaking, very slow/wrong timezone, or just very poor play). It would be good to have a confirmation step before the game starts, so that you can leave a game if there is someone in the game you do not want to play with.
Similarly, it would be good to be able to request that someone leave the game, e.g. to allow someone else to join.