To open this up, I'll offer this one up-- with shining examples bolded.
Gene Wolfes The Wizard reviewed by Katie Dean
Quote
As in the first novel, Wolfe has missed out on the opportunity to develop his characters in any meaningful way. He has set himself the challenge of portraying a boy trapped in an adult form and forced to live among adults. Unfortunately, he does nothing with this idea. We still do not see Sir Able visibly mature despite the incredible adventures he enjoys. The dialogue is still in places reminiscent of that of a child, but it is no longer by itself sufficient to convey Wolfe's tantalising idea.
The sketchy references to the seven layers that form Wolfe's fantasy world are scarcely better defined in this second novel. The first suggested that the reader would be forced to share in Sir Able's journey to understand the world to which he had been transported. This offered high hopes that all would become clear by the end of the second novel. Sadly, this is not the case. Wolfe's world remains as much a mystery by the final page as it did at the beginning. There is a skill to gradually unraveling a mystery in a manner that satisfies rather than frustrates the reader. This skill is not displayed in 'The Wizard Knight'.
Wolfe seemed to promise much in creating a world that contained elements of traditional myth and legend. Yet these references remain incoherent and under-developed. Wolfe adds nothing to the genre: there is no alternate understanding of mythical ideas and no development of traditions. More surprising still, the book fails to explore or develop its central themes, the characteristics of a wizard and those of a knight. It is too much to expect that the mere creation of fantastical places and characters can carry a story through one thousand pages on its own. It requires some kind of coherent world-view on which to build and Wolfe has failed to provide this structure.
In summary, if you are a true fan of fantasy and are looking for an imaginative romp through a strange world containing traditional fantasy characters, then Gene Wolfe should appeal. If on the other hand, you expect to find a little more depth in a novel of such length, 'The Wizard Knight' is one to be avoided.
It's pretty mind blowing-- there are many reasons to dislike a book, but writing several paragraphs about how you failed to understand what you read takes a special sort of person.