The placement of Naruto vs Sasuke
Ok, it's more or less confirmed that Sasuke will be the final villain and Naruto vs Sasuke will be the final fight.
Obito is the main antagonist. He's the one responsible for so many events in the series. Naruto's, and Sasuke's, suffering is due to him. Generally the main villain is the final battle.
Power is another factor. If the main antagonist isn't the final villain, then it's because they aren't strong enough. But, Obito is the undeniably the strongest being to ever exist sans the SO6P. At best, Sasuke can become the 3rd Juubi Jinchuriki (and gain Rinnegan) but then he's only as strong as Obito and the whole thing thing would just make the series go around in the circle.
Even Madara has a better claim than Sasuke. As an Edo he's the strongest ninja to never be the Juubi Jinchuriki. And while Obito is the Big Bad (he usurped Madara and was responsible for the majority of events), Madara was the starting point of the villainy in Naruto.
There are reasons for Naruto vs Sasuke being the last fight (mirroring Part 1, the next generation Younger Son vs Elder Son, etc.) but overall there are more against than for. Really, Naruto vs Sasuke should have happened before Madara was unveiled. Now, no matter how epic and close the fight is, we can't help but feel that in comparision to the previous major villains Sasuke is a let-down.
What do you guys think? Should Naruto vs Sasuke have already happened? Or is it the perfect final battle for the series?