An ex girl friend gave me an anecdote on gender differences years ago. A woman tried a little experiment on herself. She wondered what it would be like to be a man, and just wanting a taste, she just boosted her testosterone for a day. And what a day it was. I believe she was some kind of tour guide, where she spent the day talking to and leading groups of people. Normally, she found herself rather wound up and anxious about pleasing the group, and not wanting to assert herself and what she wanted. But with a boost of testosterone "she just didn't care". That was the defining result of the experiment for the author, and my ex girl friend as well. Testosterone was a magic elixir that dispelled worries and enabled assertiveness because "she just didn't care".

Did that increase the utility she gained? That the tour gained? Could be true either way. Could be both. Could be neither. I could say that about any of the various "improvements" to either sex you suggested - there are plenty of people who would take them the other way, And as the anecdote suggests, it may be more of a case of trade offs than independent dimensions. Once she lost her empathy and "just didn't care", her assertiveness went up, and depression went down.

Even if everyone chose to go transgendered, there's no real reason to expect us to meet in the unisex middle based on shared utility functions. It's the differences in our values that makes possible mutually beneficial exchange.