Yes, it would. We can accept some inexplicable story twists as in GF2 (drapes). We can accept the elimination of a character (Clemenza).
But what was GF3 all about? I can't really see who the hero of the story is. In GF it's about Vito giving power to his son who doesn't want it. In GF it's about the same two people: Michael getting colder and becoming a murderous beast, while his father created an atmosphere of power plus trust. The crime storys (drugs in GF, Cuba and Vegas in GF2) are just environment, even though the enemy-storys (Sollozzo and Roth) are powerful.
In my opinion, the key is: GF3 is too technical. We don't really care about Michael anymore. We are to believe that his children are his treasure, but I don't buy that. In GF we see Michael like a hesitating Hamlet, who doesn't want the power, who doesn't want to be a murderer, but unlike Hamlet he makes a tough decision. In GF2 Michael wants to protect his family, but he destroys it. What does he really want in GF3? I have no idea. If it's Immobiliare, I don't give a shit. Just like Michael in GF, Vincent has to give up his love. So what! I can't believe that Vincent really loves Mary. Not because of Sophia's acting, but because of Vincent's character. He takes women as they come. Giving up Mary is not really a sacrifice.
I know, I know, the confession and the scream. They could have put these two scenes at the end of GF2 and that's it.