You don't need Amazon's cool, nerdy word-stats features to know that. They're unreadable. Amazon shows you how, and Steven Johnson explains:
The two stats that I found totally fascinating were "Average Words Per Sentence" and "% Complex Words," the latter defined as words with three or more syllables -- words like "ameliorate", "protoplasm" or "motherf***er."
Check out Foucault and Jameson. They are literally on another planet. The top spot goes to Jameson's "Postmodernism" book which I read like scripture my first year of grad school: 53 words per sentence! Interestingly, most of the variation shows up in sentence length not in word complexity -- you often hear people complain about the impenetrable jargon of critical theory, but it looks here like the sentence length is as least as much of a culprit.