After everything that is said here though, the truth is that no matter how much planned, group game always has high chance of stalling / dieing. The big problem is that if you have, say, ten people, you have ten times the chances of all the usual cases of lack of time / inspiration / etc to come to play. You can always try to prepare for unexpected disappearances / slowdowns in game planning, but you can only do that to a point. If the premise is fun enough, game can live through unbelievable bunch of changes as far as composition of players / characters goes.<br/><br/>That brings up one of the things I was thinking about. One big strength for a game would be for it to be accessible enough so that new people would have relatively easy time jumping in. It would be good if there is some plausible way to easily introduce new people to the mix if need be in the game setting. Made that way there would be chance to survive good bunch of player changes. There is good bit of complexity compared to one on one game that comes from many characters interacting with each other, so keeping the main premise simple enough to cater for possible new arrivals later would not really hurt.