Why do people want him to have the Elder Son's eyes ? It would make no sense.
Madara said that at the end of his life spawn he unlocked the Rinnegan, which is superior to the eyes of the Elder Son and he didn't mentioned anything about first gaining eyes similar to the Elder Son. It would make much more sense for Sasuke's Sharingan to just evolve into the Rinnegan because theres no stage between those two (or there is but hasn't been mentioned).
Sasuke should get Rinnegan and I don't give a rats ass about what people think about him then being overpowered or whatever.
It would actually make LOTS of sense, Naruto needs to be in KCM mode to even take on Madara and the Juubi, by saying that Sasuke doesn't need that means that he's WAY stronger than Naruto in KCM by just using his Sharingan for the entire upcoming battle.
Sasuke needs Rinnegan.