No double posting, SAMaster.
Marriage WOULD NOT work. First off, it's not fun to put things like wifes, kids, groceries, and gas in the game. This is GTA, not "Oh God! I am running out of gas and I STILL have to get the groceries before my wife kills me!".
I think these thing would be cool in a game called "The Game Of Life". Which would be awesome.
Realistic crash physics, and ambulances and cops heading to pile ups would be cool and add realism, but there is a thin line between good realism and too much realism. It would be towtruck much shit to worry about.