For me I would like gender to be as inconsequential as hair colour, apart from in situations where it is necessary, which I think is limited only to medical conditions which present differently in different sexes and of course reproduction.
I think this is hard for most people to imagine. It would mean for example that there was no such thing as "women's clothing" and "men's clothing" except for styles where the cut is close-fitting and needs to conform to different body shapes, but that would be labelled just as sizing is now, or V-neck vs round neck or bootcut vs skinny jeans etc.
I would like to do away with the concept of "femininity" and "masculinity" as I think these are unhelpful and don't mean anything on their own. It should be possible for men or women to be strong, brutal, pretty, caring, whoever they are, really, without it being ascribed to gender or seen as a deviation from/subversion of their gender.
I also think that most people would be bisexual although gender (or sex) could be part of your "type" like how some people are attracted to dark haired/fair haired people.
If gender was seen as inconsequential then yes you would still get a few nutters who liked to throw their weight around and thought that it made a difference, but I think that sexism comes from the fact that men and women are perceived as being so different that it's used as justification for a lot of things.
I don't know if it's possible - I would like to think so but I don't know if you can erase the centuries, millennia, of cultural conditioning and ideas that people have now about the differences between men and women. It certainly won't happen in my lifetime.