Upvoted!
I think this is the most compelling argument so far.
It reminds me of the Sibfox "experiment": Russian scientists were domesticating foxes (in order to make getting their fur easier- "Let's turn them into pets, so they will trust us, so we can kill them easier!" ugh...But anyways) In the process of selecting for domesticity/trust, etc, they ended up with foxes that were dog-like: They barked, had floppy ears, and mottled fur. The fur mottling was lucky for them, since it meant that they couldn't fulfill their original purpose, and instead are being used as pets.
I can definitely see that humans would similarly have trade-offs rather than independent dimensions as well. And I can also see that those independent dimensions are not necesarily "good" or "bad" themselves. However, I do think that people will be more likely to choose to be located somewhere in that dimension-space that isn't currently inhabited by the gender of their chromosomes. (aka women in positions of authority might choose to have more testosterone, and no one would think that is "weird" or "unfeminine")
Upon reading Eliezer's possible gender dystopias ([catgirls](http://lesswrong.com/lw/xt/interpersonal_entanglement/), and [verthandi](http://lesswrong.com/lw/xu/failed_utopia_42/) and the other LW comments and posts on the subject of future gender relations, I came to a rather different conclusion than the ones I've seen espoused here. After searching around the internet a bit, I discovered that my ideas tend to fall under the general category of "postgenderism", and I am wondering what my fellow LessWrongians think of it.
This can generally be broken down to the following claims:
EDIT- Due to some really insightful comments;
I replaced men being prone to aggression as a negative, with men being prone to suicide.
I made the verbiage a little more explicit that no one would be *forced* to change, but would seek out the changes that transhumanism would have available.