My friend... I LOVE YOU. Finally someone sees what I mean! It makes no sense that Sasuke is going to get the Rinnegan AND Hashirama's cells which gives a body with A LOT of chakra, immense durability and the aptitude for Sage Mode. Due to this body he can spam to his hearts content. Add on Perfect Susano'o and the Rinnegan boosted by Hashirama's Sage Mode (or DSM) and even if Naruto obtained Onmyoudon, Sasuke could quite easily break through it.
Sasuke is essentially:
Rinnegan, Perfect Susano'o, Mokuton, EMS AND SAGE MODE (Mokuton due to Hashirama's cells which is confirmed in the manga)
to
Pseudo Juubi Jin (body only)
Sasuke has more than enough going for him to win that match-up with medium difficulty at most. Hence why I propose Naruto awakens it through means that Rikudou awakened it (through the Juubi's essence) and Sasuke gets it through Madara's way to contrast the views of Naruto/Rikudou who believe the system doesn't have to be changed whereas Sasuke and Madara want to bring radical change.
I agree with most of what you said, but there's a couple of areas I disagree with. With Hashi's cells, he get SM potential, but doesn't guarantee true SM. That would be spontaneous, and I hope if this is what happens, that Kishi gives a really good explanation for it.
I don't think all of that would be quite enough to earn a victory against a juubi jin though. First of all, we haven't seen what the sage's holy sword can do. It relies on will, and well, that suites Naruto, so that alone might make him stronger than what Sasuke would be, but regardless, yin-yang argument is officially debunked.
I think Sasuke will soon probably be a match for pre-juubi Hagomoro.
I'm not so sure it's a body enhancement persay, although you could be right about this. Remember kabuto said he is using what he has learned from Senpou and Hashirama's DNA Now this is just an assumption, but he is probably using Senpou and his medical jutsu to heal Sasuke's body with the incorporation of Hashirama's cells. Meaning Sasuke now has both Senju and Uchiha DNA, along withthe fact that he just about died, This points to him awakening his own pair of Rinnegan eyes.
So in essence he and Naruto will still be on opposite sides of the spectrum. Naruto inheriting the Sages Body (younger Brother) While Sasuke inherates the eyes (Older Brother) Just my guess but we will see how it plays out.
Yes, it'd be more of a yin powerup, but it doesn't change the fact that there's a bit of yang in there as well.