No, having a female captain (Janeway) isn't pushing diversity. Neither is having a black station commander (Sisko). UNLESS this is their main qualification and you get it paraded out every single episode how awesome it is that Janeway is a woman and that Sisko is a black guy. Because then it becomes a nuisance.
What made Star Trek great was that these things were exactly treated as non-issues. Like, say, in the future, we consider it ridiculous that we even have to mention that women can command ships or that black people hold power on stations. Even TOS had an alien as the second in command (and admittedly, it was made a theme far more often than necessary).
But what made the shows that had "minority bosses" great was that it was treated as normal, and, lo and behold, it was normal for the viewers. Remember anyone saying that a woman can't do that and that Janeway could command her ship was "unrealistic"? I don't. The only thing unrealistic about that women was her hair, what kind of futuristic concrete hairspray did she put onto that hairdo that it NEVER moved, no matter the damage to the ship?