Well i have to say that you came close, but you failed. No doubt the Sage got more powerful sealing the Juubi inside of himself. The point is that one that overcomes the power of hatred becomes immune to the effects of being taken over. Naruto was taken over by the nine-tails a couple of times at the start of Shippuden. The reason Naruto had the red eyes which indicates the point that hatred is flowing through him. Naruto was no match in terms of controlling hatred and Kurama took advantage of him. After his match with the nine-tails that's when he started to show that Kurama wasn't in charge of him anymore. Also, SO6P had the Rinnegan when he fought the ten-tails. The Sage himself indicated that the ten-tails was tough to beat by himself. The reason that he must of won was because of the Rinnegan. The SO6P is basically the father of all Uchiha's, Uzumaki's, and Senju's. He had inherited both the power of the eyes and body. So he was an entity of great power and if you add the ten-tails to his arsenal. There's no telling how great his power would be compare to Naruto and the rest of the top-tier ninjas. Sasuke might obtain the Rinnegan although it's so old i would agree the 9 tomoe one it would make it outstanding compare to the regular Rinnegan. I hope he gets that Rinnegan or something new that isn't similar to what we have seen in the past. The reason he wasn't affected by the red eyes it's because he had a strong connection with peace and the Juubi himself couldn't manipulate him it's simple as that my friend. Although, SO6P removing the hatred from the Juubi would be a complete turn off. The ten-tails is suppose to be a beast of mass destruction tainted with the power of hatred. Why do you think Madara wants the beast for himself? Because the beast is evil and merciless. We will have to see what comes next for us.