Yeah... I try to be a voice of calm with regard to the movies. And yes, I do feel the Caspian was more than just a good adaptation, I feel that it redeemed what I felt to be the weakest book in the series (upon finishing it, and then Dawn Treader, I nearly forgot all that had happened in the book version of Prince Caspian, because it became more of a set-up for Dawn Treader to me). But that's another story for another day.
What is happening right now is a dichotomy shift, or a paradigm shift, take your pick as both apply. As every time a movie comes out based on a book there are three camps that are created: (1) The book was better, (2) The movie was better and (3) The movie and the book are both good in their own right. People that enjoyed either the books or the movies fall into one of those three categories.
As long as people realize that there are people in each of those camps and that not everyone is going to love the movies, or even the books, as much as we do, then we're in pretty good shape.
All I ask for, when a movie comes out, is if the movie is edifying. I don't really put much emphasis on if the movie captured every scene that I loved in a book, because my imagination is very cinematic and I will undoubtedly have imagined scenes different than they appear on the big screen. If the movie captures what I feel to be the spirit of the story, and gets the characters from point A, where they started the story, to point B, where they were at the end of the story, then it's done the job. Then I look for moments that are the powerful ones, for the times that it teaches something. Is there something that I can learn from this? Is this a lesson that I need to learn? What am I supposed to learn from this? What about my reaction to the changes from book to film? What does that teach me about myself?
The next thing I look for is if the film is one that I wouldn't mind watching again.
Mostly though, does the movie help to bring me closer to God in some way?
Anyway... from everything that I have seen, I have no reason to believe that this Narnia is going to be as much a departure from the source material as Prince Caspian was with the restructuring of the order of the events in the book as well as the Pevensies meeting an older Caspian earlier in the story and all of that. There is a bit of restructuring as far as one event is concerned, but it makes more sense as a climax rather than a mini-battle toward the beginning (...and in my mind a group of sailors merely pushing a very large serpent over the tail of the Dawn Treader to get rid of it doesn't jive).
Anyway, I was going to say more, and wrote it, but then I removed it because I was becoming too specific. I guess I'll end with this: enjoy it for what it is, which is the best that they could do. Since the movie changed from Disney to Fox, there were many re-writes that involved a scrapped screenplay and more. What we would have seen, had the movie stayed at Disney, would have been unrecognizable. What we're getting was fought for by the very people that are making the movies.