There were protests and threats aimed at TOS for being too progressive, particularly on racial issues. TOS didn't make the command structure clear but as bridge officers and department heads Uhura and Sulu can't be any lower than 6th in command and TOS had the first interracial kiss on television. Yeah it's pretty bad looking back at it now but keeping in mind that the first season aired less than 2 years after the end of segregation helps temper the shock.