While my experience with this may not be universal, I found myself somewhat alienated by Genly Ai's perspective on the events he related. I was much more drawn in to the narrative on those occasions when it was related by Estraven. The factor that drew me out of Genly Ai's perspective was consistently his insistence on applying his particular conceptions of gender to the Gethenians he encountered. Estraven, unfettered by the need to place his world into inapplicable terms, is better able to focus in on the more flowing parts of hte story.
The main problem, for me, of his mental gendering (beyond the much discussed pronoun) was the rather disturbing set of qualities he seemed to apply to the female gender. It wasn't that his notion of masculinity wasn't disturbing, however, most of the time, when he attempted to explain or describe characteristics, it was in terms of his image of the feminine, which of course makes sense, as what he needs to relate and explain is the unfamiliar. The easiest example is that he "â€¦thought of him as [his] landlady, for he had fat buttocks that wagged as he walked, and a soft fat face, and a prying, spying, ignoble, kindly nature." (48) He also conflates femininity with a flabby sort of softness in his descriptions of the Orgota. Aside from that commonality, what he tends to interpret as feminine varies drastically, except that it always seems to pertain to relatively negative characteristics. The "landlady's" geniality is cancelled out by his volubility, and his tendency to show of Mr. Ai's room to tourists. He states (235) that women aren't mentally subnormal, but without conviction, as though he can't quite find another way to explain his society. It seems that the Envoy, and by extension, the Ekumen which he represents, isn't so advanced as one might expect of this egalitarian, Federation-like entity.
What, then, is the purpose of this alienation? Certainly, there's value in the alien narrator, as he takes us along in his explorations without the vehicle world-exploration appearing forced. More importantly, however, he makes our judgments for us. Genly Ai is a human like us, and while it's comforting to think that we would be better able to take the people of an unfamiliar society (different sexually, racially, culturally as well) on their own, appropriate terms, most people probably couldn't. Thus, the perspective we find ourselves critiquing and drawing away from is a representation of our own. While our critiques on the application of gender-roles to un-gendered individuals seems unconnected to our world, LeGuin is showing us a situation in which the human need to group doesn't just fail to be useful, but interferes with the ability of the thinker to do his job. In saddling us into the head of another human, LeGuin asks us to take the message back a step further, to examine how our applications of gender roles and ideas may be hindering us now, in ways that an alien would immediately see.