But a story like Dorian one wouldn't have place in a sci-fi universe because being gay in the future should be considered normal and accepted. You can't create a story arc like that one in ME. In a sci-fi setting is impossible to create a meaningful character story arc based on his/her sexuality because of the progressive setting of said game.
In ME player-sexuality is a better option IMO
As long as religion remains central to the human story, there will be issues with non-straight orientations. There are ways for it to play a role.
Plus, I think you are confusing two things: Being gay versus being gay and having your sexuality play a major role in your story.
Look at Steve. He's gay, but his sexuality is not really a big part of his story. His story is about getting over the loss of his spouse and moving on as a widower. It just happened that his spouse was a guy.
There's certainly room for diverse stories around sexuality in the ME series. I'd not like to see a copy of Dorian's story, since we've already seen that in a recent game. But I don't see any issues with including gay and lesbian characters.
Also, I think there's a huge difference between "bisexuality" and "playersexuality". Bioware has never done a "playersexual" character whose sexuality changes with the gender of the PC. I'd not like to see that at all and hope that they never go that route.
Well, that's rather presumptive of the what future values need end up becoming, but assuming that's the case for the moment...
Perhaps you could have a female Krogan that prefers females, but is under social pressure to help repopulate her species. That could generate a similar storyline (Yes, I know a female Krogan romance isn't terribly likely). Or maybe the Turians don't share the same human progressive ideals. Or it's just a family thing specific to the individual's background in question. These are hypothetical, but the point is that prejudice and social pressure can conceivably exist in a scifi setting, even in Mass Effect.
Good point. Salarians and Krogan are great races to explore this, if they go that route.