sasuke last powerup would be transplanting mokuton from either madara or obito after infusing it he would awaken mokuton and the rinnegan why naruto would have the juubi sealed in him then he would awaken all of rikoudos jutsus kinjutsu,chakra fuinjutsu and his hair will take the shape of rikoudo senin just my assumption guys because as it is kishi is trying to give sasuke all rikoudo doujutsu power and naruto all the rikoudo's ninjutsu,fuijutsu,lifefore.it is quite possible in naruto universe
sasuke:eye power
naruto:sage jutsu power
naruto being able to use all of rikoudo's power he would be a god.....
sasuke:eye power
naruto:sage jutsu power
naruto being able to use all of rikoudo's power he would be a god.....