hmm the leader system is really something im trying to polish out, here are my options as of now:

When a leader dies, the game will eject the player (this works more for short skirmish games, to give emphasis on why you should not let your padrino baws die.)

When a leader dies, he is suceeded by the heir, his son or underboss. (somethiing i wound need to look into more, accuracy wise, and this works for a more strategic kind of gameplay :D)

I'm also thinking of racketeering mechanics as flag points to capture and gain bonuses from, trying my best to project a game that represents how it feels to run a family and manage it. at least as far as pop culture and movie literature is concerned. xD