I dunno...
I've found comparing works in two different mediums can be tricky.
Movies are short-form narratives (at best comparable to short stories) mostly visual in focus. Novels are entirely different narratives built out of an entirely different toolkit, often aiming at more specialized and specific audiences than movies, which usually aim to be mass-market entertainment.
To me, movie adaptations of novels are akin to the CLASSICS ILLUSTRATED comics; enjoyable in their own right but not really representative of the quality of the work that inspired it. And its not quite fair to compare the visions of two different people working in different media even if one work is a derivative of another.
Bladerunner is an excellent movie but it is Ridley's Scott vision on the screen, not Philip K. Dick's. Dick inspired Scott, but what makes it great as a movie is what Scott brought to the work; his designs, the moods he evokes, the performances he coaxed out of the actors. Movies, let's not forget, are *collaborative* efforts. The actors, the designers, the soundtrack setting the mood and guiding the emotions are all tools the writer doesn't have to work with. Conversely, the writer has a collaborator in the person of the reader who directly translates the written work in purely personal terms. As a result, the impact of an evocative bit of quality wordsmithing can't always be translated to the screen.
Contrast the very first page of PHILOSOPHER'S STONE, whimsically and concisely presenting Harry's Dickensian upbringing, to the extended introductory scene that draws the viewer into the coming clash of worlds. One works out from Harry's room under the stairs, into the coming world of magic; the other works its way *in* from the viewer's world: *our* world.
What makes movies good, bad, or indifferent--as movies--is not to be found in the book that inspired them just as what makes a novel great often fails to translate from one medium to the other. For every successful, pleasing adaptation of a book there are easily a dozen failues and a hundred that barely get past the option stage. We're really talking about rarities here.
One movie I am eagerly awaiting is the upcoming adaptation of A PRINCESS OF MARS.
The adaptation comes from a team with an impressive pedigree and abundant resources and the trailer--when deconstructed and analyzed--offers hope of a pleasing experience. Yet it also warns not to expect a slavish translation: there are no moss-covered dead seas, but rather dust-covered desserts. John Carter speaks with a generic movie western accent, not the appropriate civil war era Virginia accent. The Tharns of the latter novels will be making an early appearance (obviously to set up the sequels). And the heroine, properly cast as a mature woman, is clearly going to be more active and adventurous than the haughty Princess of the novel.
Anybody going in expecting direct translation of the novel may be disappointed to find an *adaptation* to a different medium, a different audience, and a different era. Anybody enjoying the movie may find the novel to be somewhat...odd...
One trend that I am finding heartening is that with the recent evolution of *television* series, we're starting to see more novels and novel series adapted to TV. And the resulting product, typically 10-15 hours long, does come closer to translating (rather than adapting) the novels to video. There are still accomodations made (some amusing, others less so) but the longer-form medium does offer up the narrative "space" to bring in more of the tools and complexities of the better novels.
That is a trend I hope continues.