allthough we'd all want another part in the GF-series i doubt the fact whether it would be wise to make another gf-movie. the godfather is, i believe, michael corleone; this trilogy is about him and what shaped him. at the end of part 3 he presumably dies so it would be very unappropriate to give the story a swing, thereby downgrading the whole series. it was good, but it lies in the past, all we can do is look at the movies yet another time.