The Child Thief is a heavy volume, made heavier by an abundance of violence untempered by any form of morality by the majority of characters presented in the story.
The POV skips around frequently, especially in the first 250 pages, disengaging the reader from any form of emotional attachment that might be formed to the primary "lost boy", Nick. It evens out to some degree when the action truly begins, then introduces new POVs at the end that are unnecessary and cumbersome.
The author tried to pack too much in, link too many different ideas, through an amalgamation of Arthurian legend, the pilgrims arrival in America, and various mythologies involving fairies and gods.
The only place the book really shone is where the author accentuated Peter's separation from emotions that otherwise would have redeemed his character. Peter spends most of the book in observation mode, showing the reader that he feels little for the children he is "saving". What emotion he does display is like that of a person angered that one of his toys has been broken.
The ending shows that there could be hope for Peter, but it comes 494 pages too late to make the book interesting.