I loved the ending to GF3. Michael had a chance to stay out of the family business, was pulled in, and it ruined his life by killing off his family. What else is there to learn? I mean we really learned this at the end of Part 2.

I also like the irony in the end of GF3. Vito dies while playing with his grandson - which in all honesty, isn't a bad way to go. At least he was with family.

Mike dies with a lap dog by his side. Probably the only friend he had after Mary's death.

Sure we could have a GF4 or had some more scenes showing what happened after Mary's death in Part 3 - but by then, everyone responsible for killing Mary and turning against Michael is dead, and everyone has abandon Michael. I am sure Vincent continued on, but is there really any meaning in showing what he did afterwards? He's not even a real Corleone.

If there ever is a Part 4, the only reason I would see it is to see how Michael reacts to Vincent still in charge of the family. Pacino's role could be small, almost a consigliere, but he would be so depressed and saddened by Mary's death that he wouldn't be able to offer any valuable advice. However small, it would be a demanding role to play, filled with a lot of emotion - from rage to regret.

Although everything isn't wrapped up and handed to the viewer in a gift box - I believe that the endig to Part 3 is great and fitting.