“The Lion, The Witch and The Wardrobe” is, imo, inarguably the most well known and beloved of the Nania series. It stands alone.
I’m a huge fan of C.S. Lewis and the Narnia Chronicles but I do feel it is more difficult to create the same suspense for the other books in the Narnia series the way it was done for LOTR trilogy. Even as a fan of the Narnia series, I confess I’m not as interested in the followups as I was for the first film. That was my favorite book, still is. No matter how good sequels could be, I’m still partial to TLTWATW.
I would still like to see the series continue as I do still enjoy it well enough and I suspect it will though perhaps with a little more care to the costs incurred in production.
Personally I found that a very satisfying ending but as literature it is far from the light, allusive touch in The Lion, The Witch, And The Wardrobe. For persons unacquainted with Christian symbology it was likely to appear incomprehensible; for those hostile to it the thing would have been shrieked at as heavy-handed propaganda. In short, I think of all of the series except The Last Battle it might have been the most difficult to translate into a multi-leveled screenplay.
Not so The Silver Chair, a much simpler story that is, IMHO, eminently filmable. But of all of the others I'd most like to see someone film The Magician's Nephew. It's blatantly Genesis - Digory is even tempted by an apple - but done with the same light touch of The Lion, The Witch, And The Wardrobe and working perfectly well on the level of a simple adventure story for those who find the Christian allusions distasteful. And that, unfortunately, describes a significant portion of the movie's market. And, of course, for those of us who did love The Lion, The Witch, And The Wardrobe, it explains so very much, so very well.