I felt similar. I finished it but couldn’t finish the sequel. The primary idea was “intelligence can take different shapes” and I kept reading to get insightful descriptions of these different shapes but they never really came. I don’t disagree with the premise it just didn’t really get across the message very well.
The book makes pains to draw a line between consciousness (or meta consciousness) and intelligence. I don't think he really argued that intelligence is maladaptive, but does argue that meta consciousness might be.
Yea I took it as consciousness was maladaptive and sort of a local maxima that humans were trapped in which prevented them from gaining higher intelligences.