Now first off to be clear, I don't want guesses over how each of these duels would pan out. I'm speculating purely mathematically here...or sort of. :D
I've come to notice over time that there is a strange but symmetrical parallel between Naruto and Obito. The similarities between their teams. 3 members, medic chic prodigy best friend blah blah.

Then their skill progress...crap crap crap ok amazing god. I think they are meant to battle for the title of the "Chosen one to change the ninja world" haha

Only question now is...how will Sasuke fit into all of this? He needs to have a new antagonist.

Or, without that, he either has to help Naruto fight Obito, Madara and the Juubi and then turn on one another and still have enough chakra left somehow to have a massive fight. (ScenarioA)

Or get to scene to find Naruto and the team having dealt with all of that already and of course Naruto would still have enough chakra left somehow to have a massive fight with Sasuke. (ScenarioA)

Ok then what about he fights Madara then? Two? rinnegan users battleing it out or EMS vs. that and rinnegan. Ok. Say that goes well for Sasuke->scenarioA or bad for Sasuke? Madara kills him, Naruto goes berserk and defeats Madara too? Mm. So thats the only scenario that actually could happen maybe.
Can you spell O-R-O-C-H-I-M-A-R-U
I don't know how, but if you add some O to this mix, something would divert the bad guys off Naruto maybe? O grudgingly allied with Sasuke to blast damn edo Madara away? Madara and Orochimaru kill each other? ...most convinient. Makes good vs. evil chakra levels a little more equal. Because of course eventually Naruto must have a fight with Sasuke as well.