Yeah I really think you're right about ADCP being more straightforward and without as many new and interesting thoughts on empire, and I think that's definitely part of why it didn't excite me as much as the first book! Which is really too bad, but I think sometimes second books are harder to write than first books; there's a different kind of pressure on the author.

I was definitely here for the politics over the physics/biology; I guess this kind of makes Martine the opposite writer to Andy Weir, lol, and for me as a reader at least I'm much more forgiving of getting physics wrong than getting human interaction wrong!