My reaction somewhat mirrors gmw's. My overriding impression was of a really quite excellent piece of SF addressing the simple reality that aliens would be alien. Obviously, the author's choices about the nature of the differences had relevance to societal and gender issues here, but I did not feel like I was reading a treatise on human gender politics dressed up as SF. I found myself enjoying a work of anthropological SF, one that examined with detail and internal rigour and consistency the way the species' own nature and its environment shaped the culture. The grammatical and vocabulary notes reinforced for me the impression of a novel that was serious about world building and exploring difference.
In that context, Genly reminded me of Bren Cameron in Foreigner, an interpreter and analyser of difference. The closest I ever felt the author came to unsubtle moralising was when she touched on a sentiment close to my on heart, the difference between love of the physical environs of one's home and patriotism. Because the stated views meshed perfectly with mine, I enjoyed the passage greatly, but it was definitely blunt and not nuanced at all, unlike the androgyny/bisexuality that became the book's most famous feature.