I think my one qualm was the Tin Man's obsession with Dorothy, it's just creepy okay

I think the dark twist on the beloved characters made sense in their own ways and I liked the foreshadowing on who Pete really was (which i think was a nod to The Marvelous Land of Oz) and the identity of the handler. The Lion being so courageous that now he has no sympathy for the ones afraid was imo, a perfect twist on his character. The witches were all so interesting and unique, in fact the whole cast of characters was well characterized, despite being large. The intoxicating pull of magic and wickedness was really interesting to read about through Amy's character. I also found each of the character deaths extremely sad, which is a hard task for an author in the first book with a large cast and little time for side character growth.