Yeah, I think you have to take the attitude of "what's done is done." Part of the fun on punching around the ideas of putting together a GF IV (and V) script is, how can you write such a script to patch up some of the script holes left in GF I, II and III, and also move the saga forward??
Of course, III left the greatest number of plot holes. But there were a few from I and II, too:
I) We get told several times in GF I that Genco was a great consigliere? Was he, and why? What happened in the 1936-37 war that Clemenza talked about??
II) Where did Hyman Roth and Frankie Pentangeli come from? They are introduced and everybody goes to great lengths to say they had long, long histories with Vito, but how come we never saw them before?? Why wasn't Pentangeli at Connie's wedding? You think a wine-drinking guy like Frankie would miss a bash like that??
Back in Sicily in 1903, obviously there was bad blood between Antonio Andolini and Don Ciccio. Where did that come from?
III) Vincent, Sonny's illegitimate son, comes out of nowhere and wants a role in the family. Sonny had two legitimate sons, and Connie had two sons - what happened to them? Why didn't they demand a role in the family too??
And, what really happened to Tom Hagen?
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Anyway, those are just for starters. To me, the fun is writing a GF IV script that goes back and answers some of these questions. You don't have to -- in fact, you can't -- go back and erase what was in the other movies. You have to work around it and figure out the answers - connect the dots.
That's what I'm trying to do in my GF IV plotlines - explain how the Corleone family came to power in the 1920s and 30s, how Sonny made his bones, how Vito interacted with Hyman Roth and a young Moe Greene; then in the 1980s, explain what had happened to Santino Jr. and Michael (Rizzi) Corleone, and explain how they would also want a piece of the empire controlled by Vincent...
and in my fragmentary GF V script - we go back to Sicily in the 1890s and see how the blood feud between Don Ciccio and Antonio Andolini started - then we return to the 1990s, when the battle for control of the Corleone empire heats up between Vincent, Santino and Mikey (Rizzi) Corleone -
then we flash back to the early 1970s, and we see both what happened to Tom Hagen, and how the Vito grandchildren Santino and Mikey were set on the path to the family business - and finally we see in 2001-2004, when the deaths of Michael Corleone, Santino Corleone and Connie Corleone push the family into an uncertain new era...
