This is a little prediction I came up with, not sure if anyone else has the same prediction.
Once the Juubi reaches it's final form, it starts gaining consciousness. Obito will not have the ability to contain it any longer and it is released out to the open. Some time after Obito may be convinced by Naruto to be good again, doing one last good deed (maybe hurting juubi) that may be a game changer before he dies, apologising to his former sensei minato for being a failure. The Juubi now possessing consciousness, sees Naruto as Rikkudou Sennin and maybe either fears to be captured again or angered and wanting to kill him. After battling for a while (I can't think how Naruto can even stand a chance fighting against the final form Juubi), Naruto enters into the bijuu psyche plane or similar sort and confronts the Juubi. Naruto manages to convince the Juubi by giving him a kool-aid and becomes it's jinchurikki.