While the book is peppered with insights, it's really, really, really incoherent. I can't tell if it's because Hench is insane, or if it's because he's insecure about the points he's making, and therefore fluffs them up into Highfalutin Language.
At the beginning, for example, he states that the three basic components of themed design are Story, Character, and Color. He never goes on to explain why he believes that Color is as important as Story, or why it's more important than, say, Architecture. After alluding to the significance of Color for most of the book, when he finally reaches the chapter where he explains how Color can be used as a language, it's full of "insights" like, "Green reminds the audience of nature."
To me, the most revealing part of the book was the sentence, "A line is a recording of action, which expresses the revelation of life." Hench never qualifies its relevance to anything else in the book, and if you think about it for more than three seconds, it doesn't make sense, but there's a poetry to it which can be rewarding, in and of itself.