If your talking power-ups after this "mysterious person" I personally think there is a chance that whoever this person is will power-up Sasuke by getting his emotions under control. I have noticed that ever since the Match against Itachi and Obito exposing him to the truth his emotions have interfered with his fighting style. Every time he comes in contact with someone that drives his emotions he begins to fight irrationally, but if your referring to power-ups in general heading towards the end of the series some have actually convinced me the Elder Son's Eyes through through theories.