Naruto is the Sage, Sasuke is not.The Rinnegan is the Sages power thus it's Naruto too sines Naruto is the Hero and Sasuke is not.
Obito with senju DNA was able to control Gedo.
Madara said that even if he doesn't awaken the rinnegan, he will eventually be able to control Gedo mazou.
Yet Sasuke has more in common with Hagoromo. The only thing Naruto has in common is the looks when he enters Bijuu Mode which also Minato has so its not even unique to him. The ideals of Hagoromo are also alike Naruto's, but those ideals are also shared with others such as Minato ( again ) and many others. Also to believe that Naruto alone is the hero is rather strange, seeing how he is only a single part of a complete power and goal. They are both the people who will be the cause of true peace, they are both needed to defeat Madara and to achieve peace. Sasuke and Naruto are equals and they have always been that, they share an equal important role and power level. Also judging by the newest chapter that was released today, Sasuke gains Hashirama's Cells meaning he can awaken the Rinnegan now. While Naruto still lacks the power of the Uchiha which is needed to awaken the Rinnegan.
Sasuke will awaken the Rinnegan and he will be the last coming of the Sage alongside Naruto. They are both half of Hagoromo's power, Naruto is the power of the Juubi and Sasuke is the power of the Sage prior to him becoming a Jin. They are Yin and Yang an as stated, peace will only be achieved once you gain and combine these two. The way to peace was never love or power, the Sage believed it to be love alone, that is why and his Younger Song failed. The way to peace is through love and power. Through Yin and Yang, which Sasuke and Naruto are metaphors for.
The Rinnegan will be given to Sasuke.
I said that Nagato wasn't able to control the Gedo because he lacked the power of the Uchiha. Obito was able to control the Gedo because he had the powers of both clans. Madara also said that you have to have both powers in order to control the statue, that is proof that Uzumaki's aren't any more special than a normal Senju.