Excusing the late addition of this response, you also make a valid point that the theme of the leapee was probably in part for the sake of a humorous leap in but I still also stand by it making a statement of 'just because I chose this lifestyle and am comfortable in it doesn't mean it's right for you'.
Private Dancer has never been one of my favourites. Partly for the reason that Sam being a chip 'n' dale dancer doesn't really go anyway. It was as though it was done purely for the opening scenes (which are amusing). But more could have been made of Sam being uncomfortable and Al insisting that his best friend should be living the dream with women throwing themselves at him.
While a part of me does like Diana and feel sorry for her, a part of me didn't like the character. I suppose that's not exactly it. I just dislike certain aspects of her character. Her refusal to accept help from Sam doesn't really bother me, but I do think she crosses the line and is sometimes just rude towards him. I also think the theme of Sam helping vulnerable, lonely women has been overly done at this point. The ending of the episode also bothers me. Sam is leaving "Rod the Bod" in a bit of a spot. There's no reason for him to believe that Rod harbours any romantic feelings towards Diana, so Sam getting semi involved with her wasn't really fair on Rod (or Diana, for that matter).
All that being said, there are certain things I like about this episode. The scene where Sam walks Diana "home" is a nice, sweet scene that showcases just how caring and understanding Sam can be. I also really like Joanna. She's a no-nonsense sort of gal but still has warmth to her. One of the better season 3 side characters.