I think I will go for a combination of the two. My Dark Urge who is a human sorcerer! Sorcerer seems like the default class from the promotional images. I also spent some time crunching the numbers, and I will keep Gale as the default Wizard of the team (make him conjuration specialist), while I will be a powerful (and likely insane) Sorcerer.
I know I can respec the Origins, but their classes are so intertwined with their character histories and backgrounds, messing around with them might unravel the story in unforeseen ways.
Hard to tell though.
I will do Dark Urge that tries to supress it's urges, but is so afraid of them that it shoves Tadpoles into it's brain just to make them stop appearing. I think it would be interesting and kind of sad role play.