Not "lost" per se, but interesting vis a vis Coppola's recent restoration and recutting of The Cotton Club into a much better film:
I will always have a soft spot for Francis, and I've never found Godfather III quite as bad as some do though it is definitely nowhere near as good as the first two films, and has massive flaws. (Chief among them being Sofia Coppola replacing Winona Ryder at the last minute, though IMO she still has some sweet chemistry with Andy Garcia, and the loss of Robert Duvall) I know a lot about the making of the film though, and I'm not sure how much they could add or change. But given how rapturously Cotton Club Encore was received this past year, I will reserve judgment - I'm intrigued.