No need to have any of the characters from the GF universe appear in a Sicilian movie. They ultimately serve no purpose in advancing the story. While it is cool to have them there, it's just a ploy to sell books, and it worked for Puzo.

As for a new Sicilian movie, I would love to see it. I never saw the original, nor do I want to, but I loved the book.

It could be made today but it will probably have to be made outside of Hollywood for it to be any good.