Hosts can refuse to start maps that do not regularly fill completely, simply to harass players waiting to start a game; in extreme cases, they can 'camp' a map, sometimes for hours or days, making it so that nobody can use matchmaking to play that map. The first problem is simple harassment of players, and this happens somewhat regularly. I've politely asked a host who appeared AFK to start, who responded with "this is not a democracy. i am the host, and you are my guests." With the second problem, a host can camp a lobby of a game that tends not to fill completely with players - at which point it will reach the bottom of the open games list, and never reach capacity to start, effectively killing an Arcade map. I have seen this done both unintentionally and maliciously.
I propose that there be a voting system for hosts, such that a majority is required to forcibly transfer host status from one player to another.
AFK hosts and players can also be a problem. I propose an "afk kick" option. If the host, or a majority, vote that a player be kicked for being AFK, upon the passage of 1-3 minutes, the player be kicked from the lobby.