It has been generalized before that Hollywood has a tendency to butcher literature. Frankly, much like many other things, generalizations are not appropriate for all cases. Some novels are portrayed better on screen, while others lose something in the translation. However, it is a case by case diagnosis, not a general theory about a broad topic. One instance where Hollywood improved upon a novel is the 1949 movie The Heiress, directed by William Wyler and based on the 1880 novel Washington Square, by Henry James. On the other hand, the 1847 novel Wuthering Heights, by Emily Brontë, was much better than the 1939 movie Wuthering Heights, directed by William Wyler.
Washington Square was a poor novel. It was extremely long and drawn out with a dull ending. In the novel, Catherine was spineless; and the most bravery she ever obtained was used to deny herself an inheritance and turn Morris away. The Heiress was more of a fast-paced story with the same general theme and a stimulating ending. While I had no desire to continue reading Washington Square, I could not tear myself away from The Heiress. I enjoyed the way Catherine, played by Olivia de Havilland, changed from a shy, spineless girl to a brave and somewhat evil woman in The Heiress. I also found the ending when Catherine gave Morris Townsend, depicted by Montgomery Clift, a taste of his own medicine by locking him out and pretending to want him back exhilarating. The simple refusal to take him back in Washington Square is simply tiresome compared to the ending of The Heiress. It is a shining example of Hollywood improving upon a novel.
On the other hand, Wuthering Heights the film was a horrible rendition of the novel. Wuthering Heights the novel was about a demented love story between two disturbed individuals. The film made it seem as though Catherine, portrayed by Merle Oberon, and Heathcliff, played by Laurence Olivier, were just two people who would be in love forever despite circumstances driving them apart. In the book, Catherine was selfish and mean. Heathcliff was demented and cruel to everyone he encountered. In the movie, Catherine was a helpless, loving woman; and Heathcliff was just a man scorned by love who took it out on others. The movie was a poor rendition of the novel and watered it down beyond recognition.
Obviously, there are many other novels turned into movies, which could be used to illustrate the point. When it comes right down to it, these two novels turned into movies illustrate the point that all of Hollywood's renditions can be good as well as bad.