My suggestion is simple, when starting a game the player should be able to choice a rough turn base time limit, ie: 1hr, 2hr, 3hrs, 24hr,
That way people who want to play a much faster pace game can do so and people who can't take there turn for sum time will join longer based games.
There a lot of people who bring the pace of a game right down by being AFK for nearly the entire 24hrs, This can be easily solved.
Kind Regards
Cloud