This will always be the definitive cover to me. I don't really understand why it was scrapped. It's a cheesy, cartoonish depiction of the band as cannibals, and while I know it's meant to represent something very dark, it's only really implicitly so, and honestly the first time I saw it, I just thought it was the band having a BBQ.
My best guess is just that it was seen as "culturally insensitive" which, given the time and how tame this is, seems odd. It's a very silly painting of something that really happens in some parts of the world.
I think album covers have a huge impact on how an album is received, and I think that had they kept this cover, Pleasures of the Flesh would be almost as liked as the two albums bookending it.