Please let us force resignation earlier if a player has disconnected (i.e. rage quit) or if the player hasn't clicked to start the game.
I suspect that the long (5 minutes, yes?) waiting period is to allow for the situations where a bad internet connection has forced you to log out. Even if we accept that as an acceptable amount of time to have to wait...it seems like you could have a much shorter (maybe 1 minute?) wait time that would apply to situations where a player has not yet hit start, to begin the actual game.
Would not help you in a rage-quit game. But would help you in cases where you match with someone and then they suddenly disappear.
I guess it should be done for auto-matched games and the "Start Game" button. But we have to remember that players not familiar with cards often use this time to read the cards they don't know, which can take time.