A downgrade through the pictures?

After veiwing the GodfatherI, II and III, Mario Puzo's book fell into my hands. Even after watching the movies I felt that they seemed to down grade as they went through each picture, although II was still a good picture. Upon reading the novel it appeared to me that Mario Puzo definetly had a large part in the first movie and a good sector of controll over the secong, but would anyone agree with me that part III was probably written purely by Coppola?

Yes I agree. I had to say that I really didn't like the godfather III. To me it was a watered down hollywood production. Pacino, Shire and Keaton still played their charachters well, but to me Mario Puzo's talents just were not there. To me it seemed like Coppolla was ruining the family, I think hey may have been in a pact with the Barzini family to bring down the Corleone family, emotionally as well as businessly.

You raise a really good question, Signora. It's difficult to tell who contributed what to their collaboration. I offer an opinion and a guess: The fatal weakness of Part III, in my opinion, is the gaps in the plot, and the awkward dialog. These seem to me to match the gaps and dialog awkwardness in "Fools Die," "The Last Don" and "Omerta," three of Puzo's subsequent novels. I'd guess on that basis that Puzo must have had a big hand in writing Part III.