Here is a portion of a TIME article comparing recent film adaptations to their respective books. The Lion, the Witch, and the Wardrobe is among those featured, and I have copied the related parts here:
THE CHRONICLES OF NARNIA: THE LION, THE WITCH AND THE WARDROBE
-- Winner: Book
CHALLENGES: Right off the bat, the screenwriters had to commit sacrilege by tinkering with a beloved children's classic. They also had to wrestle with a strongly Christian plot that flirts with Sunday-school didacticism and had to keep kids interested despite a noticeable lack of exploding spaceships.
HOW THE BOOK WAS BETTER: Director Andrew Adamson Hollywoodizes Lion with a dreary, rote chase scene and "punches up" C.S. Lewis' dialogue with a pair of tiresome beavers with Cockney accents who engage in sitcom-style banter.
HOW THE MOVIE IS BETTER: Whereas Lewis let World War II stay in the book's background, the movie opens with a stark, scary shot of Luftwaffe bombers pummeling London. It's a daring stroke that brings out the dark strata of loss and violence that lay beneath the story. Lewis also soft-pedaled the book's climactic battle between the forces of good and evil; the movie makes it the set piece readers have always wanted. "It'd be a crime not to show a fight between a centaur and a minotaur," says screenwriter Christopher Markus.
DEFINITIVE VERSION: Nothing will ever touch the subtlety, mystery, power and charm of Lewis' novel. But this Lion is still a noble beast.
I have to admit the bit about the "sitcom-style banter" of the beavers does leave me a bit uneasy. How typically Disney, although supposedly Disney has nothing to do with the making of the movie, just the distribution. I can stomache very few recent Disney cartoons, as recent Disney cartoons are usually driven by humor, not by plot. I prefer some meat myself. I do hope the beaver side-show proves to be miniscule.