Yeah, it would've been kind of nice to know what happened to both them and the Dursleys. Problem is, just mentioning it wouldn't have been very satisfying. I'm already wondering how and when she would do it, how they would feel afterwards, how they would relate, and so on. (Hmm, kind of reminds me of Picard coming back to his real life in "The Inner Light".) Wondering how Dudley turned out, too. I don't remember if it showed in the movie, but he was definitely maturing in the last book.