One that I'd like to see more of is a zero-tolerance policy for anyone who marginalizes women in the workplace (e.g. people who file tone complaints only against women, people who talk over women in meetings, supervisors who make gender-based promotions, women getting paid less due to "market rates" etc.) I see a lot of those things still happening in tech companies, which leads to women underperforming in mixed groups.
It's an ironic tragedy of the commons.
Despite being happy with my single sex education, I'm really glad that scouting is finally been desegregated in the US as I noticed in scouting in Palo Alto that the boy scouts had much better opportunities than the Girl Scouts did. And I can be glad even though I did notice my son benefited from having a section of his life that was male-only. That will probably still be possible.
The Canadian Navy did some work pre-2000 that showed when there were only a tiny handful of women on a ship, it was hard/stressful, but when there was a 'critical mass' of say 8% of the ship female, it worked out. So they could make some small adjustments to deployment rosters and get better performance.
So 'small minority groups' sometimes need a means to coalesce a little bit and work through issues etc..
VC/entrepreneurialism is way male oriented for whatever reason. Much more so than 'regular business'. So some kind of women's meetups or whatever might help.
'Gender segregation' in education is just another thing entirely. It's about focus, social development etc..