Your question is a big, marvelous one, Mia, and I've been thinking about it.
But all my thinking so far has come to naught.
I've found no way to separate gender from need and procreation and sex.
I think that because we are gendered we do need each other--there's no way out of it until science figures out a way that men can do it (procreate,have sex,perpetrate rape, use as scapegoats) all by themselves, without women involved. What happens when men don't need women anymore?
This isn't any kind of answer at all and certainly not the kind you're looking for
and I don't mean to irritate the very intelligent gentlemen who populate this site.
'Is gender a way of reminding us that in a deep sense we need each other,
or a false set of roles leading to imagined incompleteness?'
Gender doesn't remind me of anything. It exists, it's a fact, it's not something I decide to leave at home when I go out.
Am I not understanding your question? It's like I'm being asked how I'd feel if I lived without air.
I can more easily imagine women evolving, if you will, to a single gender procreating being. But then I'm just a dumb male. On a purely personal level, I believe I am a bigger, better person for having my wife as my partner in life. As a male, I can't for a moment imagine having a similar relationship with a male, although I am equally certain that many gay men would find my life choices equally impossible. What can you say but vive la difference.