Miguel is the most popular character yet to be in the game, I'd still say he's quite a possibility.
Zafina on the other hand, she's probably dead in the water.
If Miguel returns, we'll have 5 out of the 6 new characters that were in Tekken 6. I guess it can happen but it'll just be annoying because Tekken 6 had some of the worst new character designs (until Tekken 7 trumped it in that category). Miguel, of course, wasn't one of those designs but the over representation of Tekken 6 while key characters like Anna, Lee, Julia/Michelle, and Lei are missing is not much appreciated.