Unfortunately, like with many people, there's always that one book or author where it almost doesn't matter what the director does, it isn't going to be enough. The Narnia books are like that for me. I enjoyed the movie, but I felt it wasn't very much different from the BBC production, only much MUCH better special effects.
If *I* were to do it (if someone were to walk up and hand me a ton of money and lots of artistic license), I would make the kids much older, and, more importantly, I would tell the story backwards. Or sideways. The exciting thing to me about movies is that you don't have to keep the narrator's voice or author's timeline. Sometimes, producers go too far in this respect (as my brother Joe has pointed out, if a producer is going to use a book, he/she should at least like the book--rather than claiming to do a movie based on a book and then just adopting the title).
Anyway, I would love to do a Narnia story where the story is told from a different point of view to the one you are used to. The kids are really the crux of the book so we'd have to stick with them (besides, as I've pointed out earlier, I'm not a big fan of anthropomorphized animals), but suppose the entire first part of the movie had been told from Peter's point of view? You would think, as Peter thinks, that his two younger siblings are going nuts. Of course, then you would miss the great faun scene, but that could be told in flashbacks. Or the entire story could be told by Tumnus, writing down the history of Narnia. Actually, I would opt for Edmund as the point of view, which also would excise the "first contact" but some stuff has to be excised and that's the best way to do it; the point of view can change of course; more importantly, what is shown and concealed can be handled by the camera's perspective; I think the fun of the camera is to remember (as nobody ever, ever does on Star Trek) that space is three-dimensional. Which means that the camera can enter the landscape and take a position. You don't have to stick to the book's linear narrative. You can create the story and then see where you want to stand inside it.
I do suggest seeing the movie, but I'm not one of those people who thinks that people MUST see it just because it's C.S. Lewis and Narnia. On the other hand, I'd really like them to make Prince Caspian so yeah, maybe you should go see it. But that's a financial reason, not a moral one. I adore C.S but that doesn't mean the movie couldn't have been more interesting.