At first I wanted a GFIV but after I think about it doing a GFIV would be bad either way. Centering around vincent and his generation would be boring and not carry the cool vibe of the classical gangster that we felt in the first 2 films. Centering it around Sonny and Vito in the golden days with new actors playing the major characters roles would just seem tacky and not even the same story. The best idea for part IV would be between part II and PArt III which would be Michael in the 1960's striving for legitimacy but having to go through one last major war to get there. It could start with the End of part II(michael sitting on a his chair thinking) and the alternate beginning of part III that is shown on AMC. Michael would be his normal badass self and the major emotional plot would be him regretting what he did and how he lost everything and not in the stupid way he did it in part III by crying to priests and dead corpses. Unforutnately Part III has already been made and making a GF IV that would take place between II and III would be tacky. Ideally my idea for part IV would have been best if it were part III and had been made in the late 70's or early 80's and Al Pacino were as soft spoken as he was in part I and II and not as raspy and lound as he is in PartIII