There are literally hundreds of movies that use the premise of another one. Watched the Last Samurai for the first time this weekend. Remake of the Wild Bunch and Glory.
The movies were certainly nowhere as near as good as the book, but I suspect that had any more cutting have been done, Tolkien’s material would have been cut and Jackson’s material would have been allowed to remain.
Hopefully the book will be made into a made-for-tv miniseries; that would give them enough time to be made justly, without a director’s “interpretations” being inserted therein.