And with that knowledge you should realize that the man who has displayed THE MOST powerful feats in naruto is in control OF THE MOST POWERFUL source of chakra known.
Orochimaru is seriously underpowered now, it would be counterproductive if he becomes the main antagonist after the super OP Madara, I just don't see it, Oro's powerscale is way too low even if he gets Sasuke's body