Hi,
until now in every(!) multiplayer game somebody bails out. There shot be a multiplayer rating in which the server remebers every player and his behaviour. So everybody can see if a player will bail out early. Therefore a ladder system should be implemented.
I thing every turn should have a time limit, for example 5 minutes. If the first 5 minutes are used then the next turn should have a limit of 2 minutes and the third turn 1 minute. If the turn is done in less then 1 minute the timer should be reseted and starts at 5 minute again.