Here is why according to Casey Hudson and Ray Muzyka: http://www.kotaku.co...-mass-effect-2/
Me: Tali is my favourite character. But my Shepard is female and totally in love with her. Why can’t my character engage in a romance with her? Why not have the option to have homosexual relations?
Casey Hudson: Everything new that we add still requires extra content. Some people might argue in a case like that you could just have the same kinds of scenes that just work with different characters. But we wouldn’t really want to have it that way. You’d want to take a proper approach to designing those scenes, otherwise you’d see the same scene. So we kind of pulled back and looked at where we had to draw the line in terms of how much content we make. How much should we support? We actually added a lot more romance options because we have new characters and multiple options already in the romances. So we kind of pulled back and said, “Well, the love interest is part of the story and it helps you care about the characters in a different way.” We still view it as … if you’re picturing a PG-13 action movie. That’s how we’re trying to design it. So that’s why the love interest is relatively light … That’s another thing we did better than we did before. We really lock you into character. Tali is really interesting because the whole idea of her character and what she’s concerned about and her experience and age – we kind of factor all those things, and we designed the love interests really around the particular characters because they’re all quite different. So her (love scene) is a little more innocent and fun.
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Me: (Same question.)
Ray Muzyka: In all of BioWare’s games to-date, we’ve enabled a lot of choice. So you look at games going back to Baldur’s Gate, Baldur’s Gate 2, Knights of the Old Republic, Neverwinter Nights, Dragon Age, of course … In future games we are going to enable more choice as well. That choice can come as a lot of things, it includes relationships, it includes having an impact on world events, among other things. It’s an important part of our games.
Sometimes, in some of our games, we are going to have a defined character with a more defined view. Almost like a third-person narrative – where Mass Effect is more in that vein, Dragon Age isn’t in that vein; you could see the differences between the two. It’s just part of the design and the choices made for each game. It doesn’t mean that we’ve in anyway changed our philosophy toward enabling choice. We love giving players choice, and we are going to continue to enable that for future games. That’s a commitment for some of our franchises. For some other franchises we’ve had more defined characters and sort of approaches to things, and they’ve had a more defined personality and a more defined approach to the way they’ve proceed through the game and the world.
Some game franchises are going to be slightly different but that’s part of our effort to diversify the portfolio and enable some franchises to have some more choice and some of them are around defining a more specific character, sort of a first-person versus third-person kind of narrative, but we know how important it is to our players to have that choice and we are going to continue to support that. We believe in diversity and we believe in enabling choices for our fans, it’s important to us.