I couldn't give to sh!ts about Geraci. He's nothing! He was never mentioned in the original book, the movies... anything! He should have never existed!

Winegardner could have built a Geraci-like character out of a minor character that appears in the movies or the book... someone who we know. Someone who has a face. It could have been someone as small as an extra in the movie or the book. Winegardner could have built his backstory, made him fit into the Godfather universe. Geraci sticks out like a sore thumb. Geraci was a bore, and any more time spent on him would have made the book even worse... and that's almost impossible!

There were many other directions Winegardner could have gone in, but it appears to me that he took the worst possible route in TGR.