Roger Ebert Remarked in his Review of GF III:

"Some of the dialogue scenes, especially in the beginning, sound vaguely awkward; the answers do not fit the questions, and conversations seem to have been rewritten in the editing room. Other shots - long shots, into the light, so we cannot see the characters' lips - look suspiciously like scenes that were filmed first and dubbed later. The whole ambitious final movement of the film - in which two separate intrigues are intercut with the progress of an opera being sung by Anthony - is intended to be suspenseful but is so confusing, we are not even sure which place (Sicily, Rome, London?) one of the intrigues is occurring. The final scene of the movie, which is intended to echo Marlon Brando's famous death scene, is perfunctory and awkward.

"And yet it's strange how the earlier movies fill in the gaps left by this one, and answer the questions. It is, I suspect, not even possible to understand this film without knowing the first two, and yet, knowing them, "Part III" works better than it should, evokes the same sense of wasted greatness, of misdirected genius. Both Don Vito Corleone and Don Michael Corleone could have been great men. But they lacked that final shred of character that would have allowed them to break free from their own pasts. Or perhaps their tragedies were dictated by circumstances. Perhaps they were simply born into the wrong family. "

I think he hit the nail on the head with this one.

True, his character I think is given more depth in the book, his true ideology is only touched upon in the movie, but never really explored.

Vito, basically didn't want to be subject to another man's will and was a man of his own making. The Mafia is romanticized in this mannor in the book, noble gangsters, people who don't bow to anybody else. Vito is a noble character but both him and Michael had the ability to be legitamite business men and it was stated in the book.

I think what Ebert is saying is Vito's choice (with Fanucci) and Michael's (McCluskey and Sollozzo) and ultimatly Michael's choice of allowing Vincent to take over in GF III, is their character's flaw. They had the intellect and ability to be leaders and very successful. Michael between GF II and III grew his fortune enormously and legitamized himself.

This choice would ultimatly rip apart their family and cause their children to suffer. This is a central theme of the movie. Fredo, Sonny, Sofia, all died due to their involvement within the life and although there is alot of glamour and romanticism in the life of organized crime it is ultimatly a dead end with more costs then benefits.

Incidentally if you want to read the whole review by Roger Ebert here is the link:

http://www.suntimes.com/ebert/ebert_reviews/1990/12/583903.html

i have always been (pleasantly) surprised that Ebert gave GF III a better review than Part II- they got ***1/2 and *** respectively. and he never spoke ill of Sofia-which i find admirable considering nearly every other critic did.

Can you post a link to his review of Part II.