The current chapter (631 - 'Team 7') brought about a change to the manga that I hadn't seen since Chapter 500, and it highly suggests that Naruto will end around the 650 chapter mark, rather than the 700 that Kishimoto envisioned with his wanting to continue for a year and a half more (about 75 chapters). In fact, the...
... ending will be so explosive by the end that there is only really one true way the series CAN end at this point, as all parties are present and accounted for. My theory is that Naruto becomes Rikudo and seals the Juubi in himself (but for this to work, the 8-tails has to become sealed in the Juubi which is a likely outcome as it will also increase the dramatic finale's cost if Naruto loses, thereby making the manga more... 'active'. As the 8-tails stands, he's a bit of a checkpoint - if Naruto loses the Kyuubi, the 8-tails still remains and so the true Juubi cannot emerge. Therefore, he has to be sealed away for the ending to have a proper impact.) and with the Juubi sealed in himself, Naruto brings world peace somehow. There's probably a quote about how he'll do this in earlier chapters, but I don't have my manga volumes to check them all at the moment, and I have an exam tomorrow. I will check later. I think it was something about bringing down the Ninja System.
In either case, it's the only 'true' way the manga can end. With no Ninja System, Sasuke can't become Hokage, but he can become 'acknowledged'. That's the problem with stories like this - the ending is painfully apparent, even if the hows and whys toward it aren't known. Kakishi, for example, may well help Naruto obtain the Rinnegan by getting Obito's eye, teleporting out of the false dimension (leaving Obito trapped but alive) and giving Naruto both his Sharingan and Obito's. Because he still has his right eye, he'll still be able to see and fight. The specific criteria for the Rinnegan are unexplained, but I have a good idea why - either Sasuke will have to give up his Sharingan for Naruto to get the Rinnegan, or Hinata will have to lose her Byakugan, or neither, and that Naruto simply comes near death with the Sharingan in his eyes and is thus saved by the offer of Kakishi and Obito / Sasuke.
But that's the interesting thing about stories. The hows, whys and the buildup to what is often an obvious ending, unless there's a plot twist that Kishi has yet to throw in, which is likely. It's why we read, it's why we write, it's why we love stories.
And why Naruto's the most popular manga out there, for good reason!
In either case, it's the only 'true' way the manga can end. With no Ninja System, Sasuke can't become Hokage, but he can become 'acknowledged'. That's the problem with stories like this - the ending is painfully apparent, even if the hows and whys toward it aren't known. Kakishi, for example, may well help Naruto obtain the Rinnegan by getting Obito's eye, teleporting out of the false dimension (leaving Obito trapped but alive) and giving Naruto both his Sharingan and Obito's. Because he still has his right eye, he'll still be able to see and fight. The specific criteria for the Rinnegan are unexplained, but I have a good idea why - either Sasuke will have to give up his Sharingan for Naruto to get the Rinnegan, or Hinata will have to lose her Byakugan, or neither, and that Naruto simply comes near death with the Sharingan in his eyes and is thus saved by the offer of Kakishi and Obito / Sasuke.
But that's the interesting thing about stories. The hows, whys and the buildup to what is often an obvious ending, unless there's a plot twist that Kishi has yet to throw in, which is likely. It's why we read, it's why we write, it's why we love stories.
And why Naruto's the most popular manga out there, for good reason!