Maybe it is just me. But I can't help but be struck by how wonderful the books were in their original order - like the children, we as readers were strangers in a new world, trying to piece together the parts of a magnificent mystery. Sure, the books are a tatch more logical when put in chronological order, but Narnia isn't just about the history of Narnia. It's a look at growing up, discovering faith, learning how to apply that faith when you aren't a child any longer. I love how we move through the journey of learning those things and then having to return to the everyday world of home, first with Peter and Susan, then with Edmund and Lucy, later with Eustace and Jill, and so on down the line. I realize that we don't meet all of the characters in order, but it's the timeline of putting the world together in little bits that was so fascinating for me as a child, and even now as a young adult.
I loved that The Magician's Nephew was book 6. You spend all these years learning about Narnia and the children that have lived there and visited there, and then you get to go back by a happy accident (or is it a carefully planned adventure?) and see how everything came to be before everyone else got there.
That's my two cents. At least they left The Last Battle where it was! :)
For anyone wishing to take the journey through Narnia in the original order, please read the books this way:
The Lion, the Witch, and the Wardrobe
The Voyage of the Dawn Treader
The Silver Chair
The Horse and His Boy
The Magician's Nephew
The Last Battle