The problem with III is that the storyline is too forced. II uses the backstory of Vito's early life which was part of the original Godfather novel, with the plotline of Michael's being the Don in Nevada being a logical extension of the "move to Vegas" they discussed in the original.
I think I am correct in saying that at the time of III FFC and Puzo may have needed the money, and unlike the original, III was something the studio wanted instead of it being something the director wanted.
I believe Wynona Ryder was slated to play Mary, but became ill at the last minute, and FFC made the terrible mistake of casting his daughter, who is a talented writer and director for sure, but no actress. The casting of Hamilton was a bit of Hubris also. I think FFC thought he pulled off a fast one by casting Troy Donahue ad Merle in II, and was trying to duplicate it.
For my taste Pacino overracted. Eli Wallach was just awful.
Standing alone it would be a 3 out of five star movie... along the lines of another mediocre but entertaining Pacino turn in "Devil's Advocate." Nothing more.
If there is anything good in GFIII its the acting of Talia Shire.
FFC didn't want to do Part II initially. He relented when the studio gave him total control.
Part III was a cash grab. It financed his winery.
Had Rider and Duvall been a part of Part III it would have instantly been much better...but it still had a weak script and was made too long after Part II.
A Godfather Part III that was about the final split between Michael and Tom would have been a monumental movie; as big in scope as the Godfather Part 2. Instead it always feels to me like two poorly coordinated stories; one a sort of corporate thriller about a bad guy trying to wash himself clean with a big acquisition while his enemies try to prevent it, and the other a sort of passing of the torch from the king to his heir (Michael to Vincent, much as Godfather 1 was about Vito to Michael).
It's these two poorly sewed together plots that drive me nuts about the movie. I get the whole Vincent-Mary plot line, even if the wrong actress was cast. I get the whole Immobiliare plot line, though George Hamilton sort of plays a rather dull "hotshot" corporate lawyer type that gives us nothing emotional to attach ourselves to.
If I could not have got Robert Duvall to come back (and I would have paid him whatever he wanted, even costar billing with Pacino), then I would have eliminated the whole Don Altobello angle. It really does poorly fit the story, and always feels patched on. I would have played up the whole "enemies in high places" angle much more; sort of a Sollozzo-Barzini writ large. You could still have worked in the other points without a distracting never-before-seen-but-so-very-powerful Don.
