I doubt any profanity in Godfather III influenced any ratings. Godfather III had so many problems with it that's why it didn't live up to the first two films. The story line was mediocre and complicated, alot of people dislike the fact that FFC's daughter played Mary and a cousin-cousin relationship all helped mold the fate of that film. You cannot blame it on any swearing.

The vice scene in Casino is awesome. It just sounds like your a little squeemish. You're gonna have to toughen yourself up a bit.