I've been thinking that a new Traya could be the Exile and I'll describe what I think, with a canon Jedi Exile, Light Side Female. She betrayed the Jedi Order, following Revan and Malak to war and when she was exiled, I'm guessing she felt betrayed by the masters, when exiled. When she met Kreia, she tried to lure the Exile to the dark side, with her teachings. The Exile rejected all times and was betrayed by both the Jedi Masters (Who had fallen to the dark side in my opinion) and Kreia. Atris betrayed her, when she fell to the dark side. On Malachor V, the Exile tried to bring Kreia back to the light, even after everything she had done, but Kreia wouldn't return to the light side. My guess is, that after all the betrayals the Jedi Exile suffered with, she could become the next Darth Traya, but this is my opinion and you can disagree with me. I personally, think that if the Exile returns in KOTOR III, I would like her to fall to the dark side, after all she is the supposed death of the Force, unlike Revan.
Sorry, I don't usually make long posts like this and if I don't make sense, it was because I was tired.