[greyhavener]

Are the immoral qualified to evaluate another's morality? Perhaps that is why Tolkein, Lewis, etc. believed morality is defined by a higher power.

Back to the original question about valid criticisms. Valid is a relative term, but there are criticisms of Tolkein, Lewis, L'Engle, LeGuin, to name a few that are part of the same Twayne series that does criticisms of Shakespeare, Milton, Hemingway, etc. Many fantasy authors are included in many standard literary reference tools used by students, and there are also specific critical works taht address only fantasy writing. Check out a large public or university library if you want to read more.