I tend to think its progressiveness, though real, has been and is overplayed somewhat. Consider The Cage's Number One versus Nurse Chapel, for instance - now what might that have been? Or Turnabout Intruder. And no gays in canon as yet, AFAIK - Frakes shouted down over having a male play Soren in The Outcast, Goldberg having to insist on changing her lines in The Offspring, Andrew Robinson told to stop playing Garak as gay, ditto Dominic Keating.
Which isn't to say Trek's always shirked controversy - the much-vaunted Plato's Stepchildren, (which IIRC, in shooting order, wasn't even the first interracial kiss on Star Trek
, never mind all TV), and Data's musings on the possible efficacy of terrorism in The High Ground. But I think a tendency to rest on past laurels has bred a degree of complacency where time and again, morally complex issues are foisted onto abjectly alien species to sugarcoat the intention - when audiences have by and large outgrown the need for such 'coding', except in some cases with regard to religious matters.
As for 'inspiring', well, there were a lot fewer shows and a lot fewer channels back then. My guess is that it was easier to stand out. Just an opinion.