If a boy is making girls uncomfortable when changing or toileting then that boy needs to be excluded and taught the error of his ways. The answer surely isn't to hide all female bodies from all males? That causes major problems further down the line.
Well, since society has not been willing to teach boys to not make girls uncomfortable at any point in written history, I would not trust this to change all of a sudden. Perhaps it would be claimed that it is done, but it would not be done. Girls would be told to just suffer in silence, that "boys will be boys."
Separate changing rooms and showers and bedrooms work. Not perfectly, but much better than any newly introduced policy would.
Considering that as opposed to the times in which Jane Austen wrote her novels, it is now considered perfectly okay for a woman to go on a date with a man without chaperone, but society does not manage to punish men for date rape, I am not very enthusiastic about removing more of the sex separation.
So far, the results of giving men more access to women seems to have been an increased risk of rape, with the conviction rates remaining low.
And while it has advantages for women to be able to socialise with men without it damaging their reputation; I see no advantage in allowing men into women's showers and changing rooms.
I would feel rather limited in my freedom if I was not allowed to meet with male friends, but I cannot recall ever having missed men in the women's showers or changing rooms.
Perhaps we should first make it legal for women and girls to be topless in public, before suggesting that women and girls should be forced to be naked in front of males in changing rooms and showers.