How many shows other than the TNG being made in the late 80s or early 90s could you say was more progressive?
I'll see your TNG and raise you
Cagney & Lacey (1981-88), which not only featured two women as the eponymous police officers/action heroes, but also dealt with gender discrimination, rape, AIDS, abortion, alcoholism, and racial bias in law enforcement. TNG had Tasha Yar (for half a season), a couple of female doctors, and a female psychiatrist. So for six of its seven years, the major female characters were in the nurturing professions. Not very progressive.
Soap (1977-1981) featured the first gay character in a major role on American TV.
Dynasty (1981-1989) included a gay character in the main cast,
thirtysomething (1987-1991) had a gay recurring character, and long-running soap
As the World Turns introduced its first gay regular character in 1988. TNG? Poor old Soran, a character played by a woman, who wanted to be a woman. (SF Debris describes the episode sardonically as "One brave woman's quest for cock in the face of lesbian tyranny." Jon Frakes says the J'naii should have been played by men -- and that he would still have kissed Soran.) Not very progressive.
TNG did have two actors of color in the main cast, one of whom played an alien. Not terrible, but not significantly ahead of other dramas in the time period, either. Not very progressive.
I submit that TOS was actually more progressive for its time period than TNG was for its. Having a black woman, an Asian-American man, and a (pseudo-) Russian as officers? Black performers playing admirals, doctors, and computer scientists? Women as security officers, lawyers, and planetary leaders? Shows addressing racism, the Cold War, and problems of automation? In the 1960s? Now
that's progressive. And I haven't even mentioned
the kiss.