I would prefer a woman who does have prior experience with women, personally, and prefers women. It was one of the things I liked about Leliana, it was believable that she found women attractive, and she wasn't just drawn to the main character because of plot convenience.
Other than that, I would really, really want a strong, independent woman who is slightly snarky without venturing into full on tsundere territory. Someone who doesn't need to be rescued, and would gladly save the day for my character once in a while. A good sense of humor is a must, too.
Oh, and full lips, dark hair, and generally hot would be great, too.
But oh wait! Every female character I have fallen in love with in Bioware's games (Bastila, Morrigan, Miranda, Viconia...) isn't into women at all. If Bioware sees my requirements, there is no way the next awesome female lead will be a same sex option.
Nobody at Bioware read this post!!!