I think the basic idea of the Shrek series is good - that everyone deserves love, whether you're good-looking or ugly. In fact, a lot of good-lookers are finks inside, men and women. They hide an ugly nature and some very ugly people are wonderful. Can't read books by their covers.
One of the positive things about Shrek 3 was how it makes all the princesses quite ordinary women, all princes normal, cowardly, self-centered men and all the animals quite lovely. Which is real enough...;)
... but it's realism has nothing to take home, nothing of value for anyone who's avoided ADD. Shrek lies, steals, uses violence to get his way ... he's an ogre who's very much like an american boy in the bush era. Nothing interesting.
Disney and pixar/dreamworks both seem to be run at this point by hentai-wannabes and this is the result of their lacklustre day-job. Bah.