Roddenberry had to resort to extreme measures to get the black/white kiss on TV at all. Apparently he destroyed all other cuts, and presented the networks with a fait accompli.
But from the racist perspective, the worst character was Uhura, the communications officer.
The actress who played her got to meet Marting Luther King who said that Star Trek was the only programme he liked his kids watching.
Uhura wasn't a black woman...
OK, she was a black woman, but she didn't have a black female role. She was a smart person with a responsible job, who just happened to be a black woman. The normality of her position was the message.
There is an underlying theme in much SF that in a universe containing beings with 12 heads, composed entirely of energy, or are 1 millimetre or 1 mile high, skin pigments don't count for much, and there is a ST episode which pushes that message hard, indeed with rather crass over kill.
Stargate SG1, the longest running SF TV series is a pretty unremitting attack upon superstition and/or organised religion, though their nerve failed when time came to attack the Jesus myths.
It also has a female physicist who kills people with knives and machine guns. She also blew up a star just to make sure the bastards were dead.
Samantha Carter is easily the best female role model in any mainstream modern TV.