[thejeff]

Obviously there's a difference of opinion there. Or you're thinking of the Hobbit, which is very much a children's book, but charming in it's way.

I'm not sure what you mean by naive? I'll grant they may not be sufficiently grim and gritty for some and he leaves out the sex and the swearing, if that's what you mean by "mature fantasy". That's a product of his times as much as anything.

He also had a fundamentally optimistic outlook that's not much in favor now, based in his Catholic faith. That may pass for naive to the casual observer.

Tolkein's writing style is an older style, which may be why it seems dry and arduous to some. I find it elegant and at times poetic, but I like a lot of older works.

I enjoyed the first of the Song of Fire & Ice books, but it went downhill after that to my tastes. He takes his reaction to "fantasy literature coddles the reader" almost to a parody of the other extreme. By the time I gave up reading, he'd killed off most of the characters I had any interest in.
If Tolkein is naive, I prefer that to the "no good deed goes unpunished" cynicism of Martin's books.