Science fiction writer Lucius Shepard gives his review of "The Return of the King." I don't agree with everything he said, but he seems to feel the same way I do: the movie (and the trilogy) are great spectacles with a lot of entertainment value, yet filled with many faults. His summation seems pretty on point:
"The trilogy has now gone into the popular culture, standing as an incomparable feat of technical magic, and criticism of the project will seem no more than dust raised by its vast passage. Still and all, a quibble or two are not completely out of order, and I submit, for whatever value it may supply, that LotR’s hallucinatory content—giant spider, F-16 pterodactyls, super-mega-mastodons, et al—might have been better served with a lighter touch of magic, a few less epic sorrows, and a smattering of sufferings more mundane."
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On a separate point, for what it's worth, Shepard brings up the Sam and Frodo dynamic and how they represent a 19th century British view of the relationship between servant and aristocrat. And that is certainly there in both the movie and the book. But when I was a kid reading the books, I saw their story as one of loyalty between friends. Sam was a good friend who supported Frodo right to the end. In fact, I saw LOTR as Sam's story (and he is the last person to write in The Red Book, the book you see finished at the end of the movie.) And while Tolkien certainly had the class dynamic in mind, I think he also saw it as a story of friendship and loyalty.