Given the fact that a vast number of female characters are sexualized in video games, I appreciate BioWare veering away from that in Inquisition. I welcome female characters who are sex positive like Isabela was, but I don't need that in every game I play. What I need more of is female characters who are presented as normal human beings without being defined by their sexuality (like Leliana, among others). I also appreciated BioWare having a sexualized/sex-positive male character in this installment--Iron Bull.
As far as the portrayal of Dorian as a gay man, I'd argue that there are all types of gay people in the real world, so why shouldn't we see a diversity among them in fiction? There are gay men and women who are not only open about their sexuality but discuss it frequently and incorporate it as a very major part of who they are--their decision to do so is just as valid as gay people who don't specifically discuss it as often. And seeing as how David Gaider put a lot of himself into Dorian, I'd say that he's a very deep character who appeared very realistic to me. He's one of my all-time favorite characters in the Dragon Age franchise.
The only minority character I've ever had a problem with in Dragon Age is Serendipity. They majorly screwed the pooch on that one, but they did at least recognize and acknowledge that misstep.
BioWare isn't perfect when it comes to diversity, but I think they do it FAR better than most of the game developers out there. Addressing diversity in video games is still a relatively new thing, so it's going to take a while for the video game industry to get it right as a whole. But I think other developers should look to BioWare to see how it can be done.