In Gene's defense, despite all the flaws of the original, it was revolutionary by 60's standards.
1. Sulu was one of the few Asian characters not played up as some cringey stereotype. Takei and other Trek cast members can confirm every Asian actor was fighting for the role Takei got because it portrayed an Asian as a competent human being who acted professional and had a position of respect and authority that didn't play into stereotypes.
2. Uhuru was a black woman who was in high ranking position of authority (she was a senior officer in fact).
3. There were plans to flesh out some of the characters who didn't do a lot, but Roddenberry had to fight HARD to get a lot of what we did see, which again, multiple Trek cast members could confirm.
4. Roddenberry had a lot of his dumber ideas quashed as a result of #3, so while what we got was flawed, it was a hell of a lot better than some of the dumb shit Roddenberry had planned (like trying to turn the Vulcan IDIC crap into a cheap excuse to sell crappy merchandise, which Nimoy recounted in his latest autobiography as something he was glad never took off)
5. A lot of the women hangups were partially his fault, but some of it was partially crap he couldn't do anything about. Behind the scenes, Nichelle Nichols almost quit because off camera, she was getting treated like a second class citizen due to being black despite what was shown on camera, and a few of the other women, white or otherwise, also got shitty treatment when the cameras weren't rolling because 60s sexism was really that bad.