Why would anyone in their right minds let comics drive the movies anyway? The money to be made from movies is vastly greater. The success of the franchise depends on the next movie being a hit. The comics can be a big hit by comics standards, but that money is piddly by comparison and won't get more movies or a TV series greenlit.
Talk about putting the cart before the horse. Orci should have said that to the interviewer, although it would probably sound too business focused and crass for a fan audience, even though it's just reality.
The villain will be whoever he needs to be, to maximize box office potential. Gary Mitchell fits the Darkness taglne well, and his story is nice and simple, ready made to be told within the constraints of a two hour movie, and it's different from the vengeance plotline of the last movie, which they won't want to repeat.
Darvin is an iffier fit - like Khan, there would be too much backstory to explain (why does he look human? What are the Feds and Klingons fighting about?) But he does fit in with the earlier efforts to cast a Hispanic actor in the role, which would fit Khan or Darvin but not Mitchell (although it could have been a PC attempt to bring a bit more diversity into a heavily white male cast or beef up box office in Latin America.)