Well if he was too far gone to change, his "Ones Who Know Everything" arc wouldn't be very suspenseful, because there wouldn't be anything riding on him making a major decision about his motives. For now, I think he's going to emerge from this current arc with a more complete objective based on an understanding of the events that have shaped his world, but his ideology/viewpoint will still set him against Naruto (but also against Madara). Basically, I THINK sasuke will still eventually fight Naruto, but Sasuke will no longer be anyone's pawn or just an impulsive, angry kid.