I have to diagree. If you look at GFII - the parts of young Vito are just terrific, even though there's no plot at all. We just see how a young man becomes develops. Also the 50's part is not really what you would call a plot.

Compared to that there's pretty much of a plot. But the characters aren't interestig anymore. And, I repeat myself, there's hardly any single good scene in the whole movie.