Did you like the end? Would you change it?

I like the end. It ties the fantasy and reality aspects of the narrative quite nicely. It also sets up room for more adventures. The children tell the Professor the story in order to explain why four of the fur coats from the wardrobe are missing. He believes their story entirely, and assures them that one day they will see Narnia again. He repeats what Aslan said to them as they had assumed their thrones: they will always be kings and queens of Narnia.