Well, I'm cix, not trans, but my impression based off reading and listening to some trans perspectives (by no means all) is basically that trans folk can't be reduced to a single opinion. Some trans people probably prefer to just be known as their preferred gender identity (i.e. "I'm just a man.") while others might feel that their trans identity in and of itself is very important to them...or a mix!
There's also non-binary folks...genderqueer people, for instance, who break out of the male-female binary entirely. Gender fluid people...Lots of different identities.
Some of these are culturally bound (Two Spirit comes to mind), and Thedas might have its own culturally-based gender identities. The Avvar might have genders beyond male and female, for instance...I dunno, maybe their Shamans forsake gender as part of a cultural tradition, seeing them as beyond the everyday of male and female because of their magic or something. Or maybe the Fex have a ceremony where at the age of 13 they choose a new name for themselves, which includes forging a new gender for themselves, and this is celebrated as a coming-of-age thing sort of like a birthday. Maybe a culture we haven't seen believes that eye color dictates a person's role in life, and they largely ignore gender except for breeding purposes. Who knows? Culture can do lots of things.
I think as far as PC characters go, it would be nice if they allowed the player to choose race and class like always, but then have us pick sex and gender separately. (So I'm playing a human rogue female who was born male). Or maybe they could at least separate voices from gender so we could theoretically have a female character (female presenting) voiced by John Curry.