Some people say that they killed him off like that so that it would show that he died alone. Another is that is FFC's way of saying "I don't want to do this anymore!". It also added a lot more dramatic effect. At the time it was an appropriate ending IMO. However-Mario Puzo's idea of a 4th gf got me excited. As many people would agree with me, I don't want a gf centered around vinnie. I would have loved to have the movie centered on Michael trying to deal even more with the guilt with maybe a big plot twist only FFC and Mario Puzo could come up with-and of course the flashbacks on Sonny.

However, Puzo is dead and GF just should not be made without Puzo-otherwise I would have loved to see GF4.

Oh and by the way, Puzo, before he died, planned on the present day part of the film be how Vinnie spins the family to the ground with wars and a lot of drugs-not my cup of tea but hey its Puzo and I'm sure I would have liked it.