The Godfather Part IV would be overkill. I like the trilogy as it is, and even GFII was on the edge (although some people think it was over).

Who would write it? Puzo is dead. Who would play it? Andy Garcia? That's a possibility, what would be the story? Special event to open (marriage, first communion, order of San Sebastian), some gangsters plotting against Corleone, some special event in the end (baptism, opera) where all the crooks are killed?

No, the recipe of the Godfather is good, but another more movie would be a parody on itself. Sorry for those who are in favour, but it has ended in beauty.