By the way, it should be mind bendingly obvious what it takes to activate a Rinnegan from an EMS. Madara said that his Rinnegan activated shortly before he died, and (supposedly) he was fighting Hashirama right before he died. Given how Kishi has tried to make as many parallels between the Hashi/Madara fight and the upcoming Naruto/Sasuke fight, lets take one element we know will be in the Naruto/Sasuke fight and apply it to the Hashi/Madara fight. Forgiveness/Redemption/Letting go of Hate
When Madara was dying, he probably admitted the error of his ways to Hashirama and asked for forgiveness. Just as the feeling of loss produces a Mangekyo, the feeling of redemption/humbling oneself probably produces a Rinnegan from an EMS. The net result of this?
When Naruto finally succeeds in his manlove mission for Sasuke, and Sasuke asks for forgiveness, Sasuke will magically gain his LOLHAX Rinnegan eyes. After that, there's probably a 50/50 possibility that Sasuke is still too injured to fight, and gives his eyes to Naruto so Naruto can beat the final form of tobi/whoever is the final enemy at that point.
Naruto is really going to be Narujesus when he adds the rinnegan to all the other bullshit he has now. Hilarious.
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Also, the entire "improving beyond your prime" shit was probably relating to Kabuto somehow giving Madara the knowledge of how to use the Rinnegan. Since in the above theory, he died pretty soon after getting it, and thus didn't have much time to actually learn techniques relating to it.