I agree with the above points, but what I liked best about the book was its basic concept--tying together threads from "For The World Is Hollow..." and TMP, in addition to the 'Kirk gets into a fist fight with (a) god' and 'Kirk talks a computer to death' tropes. It was an engaging look into some of the repercussions of Kirk's actions during TOS and recurring themes in Star Trek.
Christopher did something similar in DTI: Forgotten History
, regarding Kirk's reputation as a temporal menace. I really enjoyed that too--there's a good reason Christopher's books are some of the only Trek fiction I've read in several years. He's really good at picking up threads from Trek's history and producing thoughtful, meticulously-researched, and entertaining explorations of those threads' significance in a larger Trek universe.