Godfather made crime movies about mobs happen and thus, crime movies about mobs turned to shit.
The Godfather movies really have no interesting story of why the characters would kill for something other then money, other then michael corleone in one scene killing the people responsible for his father's attempted assassination.
If you want to make a crime movie that doesn't have any good guys then have it explain how the criminal organization works, did godfather do that? No, it just threw out lingo, Kisses of Death, and a mumbly fat man.