Now it would be my take that on one level the arhcetype of the mafia world is a personification of justice. Justice is swift and absolute, as in Vito's empire. Although Vito is no saint in his actions, he is almost an ideal leader. He is fair, he is brave, he is just, he is charismatic, he abides by laws and morals (although not society's). Infact every single portrayal of him is one of high esteem, in the book, his portrayal is one of someone who simply does not want to play by society's rules and wishes to live by a different brand of justice. In this sense he is no more than a rebel.

Michael on the other hand is a tight fisted ruler, by GF2 he is certainly more of a dictator than a fair person and rules more in a totalitarian style. The death of Pentangeli and Fredo by his hands is really evidence of an "unjust" punishment, in the sense that they did F* up, but they were wrong and did repent. In this sense he can be contrasted and GF1 is an examination of more a utopian set up, maybe not exactly vs a dystopia.