After watching Part III for another time last night, and really not liking the direction they took with some plots... I am definite that IF they make another movie, that it would have to take place in the old days, before Godfather Part I.

The plot has been stretched so thin after Part III that it would probably turn out to be even more of the same. While the Young Sonny and Vincent outline sounded good - this franchise is about Michael and Vito.