Sektor and Cyrax's humans forms could easily work as DLC, with the same moves, just the mechanics would be different, for instance Sektor could have some backpack rocket shooter, something like what Iron Man's War Machine has on his back/shoulders (not saying it will happen, but it could). I think it would be cool to see them as representing an in between step from human ninja to fully automated cyborg.
As a side note, I don't want to see them as black and white. I should hope they are Asian. It might be cool if Cyrax is Khmer or some other SE Asian since I don't think there is any in Mortal Kombat yet, and since it wasn't specifically said that Cyrax is African American, or any African for that matter, it would be ok, the skin-tone and a lot of the facial structures wouldn't be that much of a stretch.