Considering that TOS did break several boundaries (A black female in a senior officer, if not a command position on the Bridge, tackling racism through allegory - Let That Be Your Last Battlefield - Put a Russian on the Bridge of the ship in a senior position right smack dab in the middle of the Cold War, along with other issues) and tackled certain issues of it's day through allegory, once has to cringe a little bit about how a certain level of blandness did creep into it as Series such ad TNG et al came along.
Don't get me wrong, TOS did have it's problems, but for it's day, it was certainly ground breaking for a Sci-Fi show, let alone a TV show of that era.
All this - and don't forget the biblethumpers who wanted Spock dropped from the show because he somehow reminded them of the Devil.
One could make an argument out of Jadzia Dax challenging binary gender norms (in a very, very milquetoast way), whatwith Dax having zero concerns about going from living an entire life in a male body to embracing living in a female one (albeit, both bodies seemed to display none of the neurological complications at the heart of gender-dysphoria in many *trans people, so one could argue that Dax' 'transition' was a purely spiritual one), and Cisco's affectionately calling her 'old man' every so often.
I really liked what Jolene Blalock and Connor Trineer did with their respective characters in Enterprise - to me, it was a very slow and very subtle challenging of gender-roles, at times driven by Blalock's mastery at weaving into her lines the infinitely slow evolution/erosion of T'Pols emotional control over many episodes, at other times by Trineer being man enough to be the Enterprise's version of Firefly's Kaylee (Cheerful, adorable hornball country-bumpkin-and-genius-mechanic - and the first pregnant cisman in the Federation's history) that culminated in their troubled relationship-attempt, which I thought hinted at a striking (and touching) role-reversal of traditional gender-norms. To me, it felt like Trip finding the strength to show the hope, anxiety and grief that T'pol could not express in all but the most painfully restrained gestures acted as a kind of
"Verfremdungseffect" - highlighting the essentially pathological underpinnings of stoic masculinity gone toxic by showcasing the 'familiar' in a 'foreign' framework.
So while one could argue that none of that was as groundbreaking relative to the prevalent cultural mores of the times as TOS had been, I don't quite see the Franchise
totally abandoning that heritage.