A thought occurred to me a while ago, though, that seems to offer a third way of looking at the question. Occasionally, book and movie versions can stand along side each other, with the movie offering a different way of seeing the book that isn't worse or better - it's just different. Take Gone With the Wind, for example. First of all, in the book, Scarlett isn't beautiful. Mitchell tells you that in the first paragraph. Could you imagine the movie-version of Scarlett O'Hara as anyone other than Vivien Leigh? Me neither. She becomes her own Scarlett, a character related to the original but different, and not to be confused, in my opinion, with the first. Then, there's the bit about Scarlett having children with all of her husbands, not just Rhett. (Sorry if you didn't know that.) Clearly, the choice to just have Bonnie in the movie focuses the importance of her relationship with Rhett and raises that marriage above the others. In the book, it's realistic that she would have had all those children and it makes within the context of the novel.
I don't ever compare GWTW the book to GWTW the movie, because, well, they're just different. I put the Harry Potter series, The Great Gatsby, Rebecca, and Sense and Sensibility in the same category.