A fantastic article. To defend poor old Tolkien for a moment, the vital thing missed by many who attempt to write their own fantasy epics is Frodo and the other main characters in The Lord of the Rings all have to face the evil within themselves as well as external evil. The choices they face do indeed challenge their beliefs and values, and they are changed. For instance, Frodo essentially fails at the last hurdle, claiming the Ring for himself, before Gollum's fateful attack that ironically destroys both him and the Dark Lord.

On a related note, I have occasionally run into trouble with fantasy fans by daring to suggest that the reason Tolkien's work succeeded so well in the first place isn't primarily due to the minutiae of orcs, elves, wizards, and so on, but because it contains universally relatable themes. Here's a brief piece I wrote on that subject.