Can we get an optional kick message when kicking people out of a lobby? It'd also be nice to be able to choose whether the player can instantly rejoin or not.
I've been kicked out of a lot of lobbies immediately after joining, and I generally assume it's people who don't want to play against people that are higher rank/level than them, or something like that. It'd be nice to know. Naturally some people would abuse this, as a way to send a message to someone that they can't reply to, but I think it'd have a good shot at improving game etiquette. If it's something like not wanting them to use a certain race, a reason box popping over might remind the lobby host to actually ask the person to change races, or something like that.
As for instant rejoin, sometimes you run into an issue where someone isn't readying up, or something like that. While you don't want them delaying the start of the game, if they get back, there'd be no issue with that player rejoining. But that's a rather minor thing.