As we all know, the endings of all 3 existing GF movies are incredible, so if you had the chance to give your input to the end scene of GF 4, assuming it took place between GF 1 and the Vito scenes of GF 2, how would you end it? Me, I would have a scene of Mike telling Vito he will always be a Corleone, but never be an "olive importer" or is that lame?

That sounds like realistic dialogue. I could believe Micheal could say it, as a complement implying Vito was bigger than life and that the Corleone name is bigger than what is only a job. A way to make money, thats all. What other contexts do you see.

well, while i would prefer that IV end with the death of Connie, under your time frame i would have Vito looking right at Michael and saying "You are going to have to grow up someday"

Vincent does something or other to bring the Corleones back as the most powerful family, only to compete with Anthony who wants his share...actually, that's dumb, but I don't know.

if i wasd to wrote an ending it would be that the corleone family would go under and be destroyed at the hands of Vincent