OMG - "Elfstones" is going to be a movie? That's my favorite of the first trilogy, as well. The reluctant (& initially inept) hero, the "wrong son" Prince Ander who becomes king, evil disguised as good, the courage of the Free Corp, noble self-sacrifice and ROMANCE!
I disagree that Terry Brooks writes for teens. Granted I read him as a teen b/c that's how old I was when those books came out. I went to a very conservative parochial boarding school for high school, and speculative fiction was severely frowned upon and confiscated (even as they prayed for your poor misguided soul!). My roommate and I took turns reading aloud, whispering under the covers w/a flashlight so we wouldn't be caught by the hall monitors.
I think, like all fantasy writers, he coaches universal truths into a forum for the masses. Most genre fiction is written at a sixth-grade vocabulary level, so it can be read and enjoyed by all. Literacy is still an issue, and my daughter's five word rule (if you don't understand 5 words per page, it's too hard for you) still applies. Who wants a book so high-brow everyone puts it down because they got sick of going "Huh?" I know LOTS of adults that still read Terry Brooks, Mercedes Lackey, Elizabeth Haydon.
It's modern mythology. I don't think people are ripping off Tolkien. I think, like Joseph Campbell, he's the base of the pyramid from which all other fantasy writers build. I loved Peter Jackson's vision. I have the Joseph Campbell lecture tapes, where they seriously dissect "Star Wars." There's the saying "there are no new ideas/plots, just new ways of presenting them." It's true.
I write high fantasy romance for Samhain Publishing. I have a heroine who discovers she's not what she thought, I have a hero who becomes the very thing he swore his entire life he'd never do, I have noble self-sacrifice and accepting the different, I have enemies working together to triumph over evil. Universal truths are never cliche.