I personally don't ever want or need gender reassignment surgery, but as a person who has trans friends, I would love to see them feel at peace with who they are and to have a body that matches their brain. I can't even see a negative to this question. People wouldn't just "change gender" on a whim.
Man and lady is meant to be as they create children. I would feel it bit freaked out when every hot lady is actually a guy with a vagina. It is a bit pervy in my opinion. Why do you need to have a different boy to be happy when you could go to sports and make friends, adult education, get a job etc.
While I am for the general practice of sex change, I am against the "perfection" of sex changes. Absolute changes in human genders can be misleading to opposite genders who are looking for relationships. While "perfection" of a change from male/female to female/male is legal and moral on its own, it severely increases the problem of manipulation. Again, I'm okay with people who had sex changes, but I'd like to know whether a person is or isn't the gender he/she claims to be, especially before I engage in a relationship with him/her. In other words, I'd like to know that the gender I am engaging in sex with is indeed the gender that I think. In recent history, there were some murders of individuals undergoing sex changes, and this wasn't just due to the stigma of the matter. In one real scenario, a female had entered a relationship with another male. But the female was actually a male himself. Though the latter male wasn't the one to commit the murder or cause any violence, there was still controversy.
I just think there needs to be some way to tell if a person has had a sex change before engaging in anything. "Perfection" of the sex change would nullify any evidence.