Well, Derp.. Even if this is true. Isn't this a punishment to the human race as well? The Juubi is the progenitor of destruction, yet the Sage expects people to figure out how to make peace with it? What is the Juubi going to be more accepting since it will be complete now? I'm saying this because it will have all the tail beast chakra within it. Will Naruto make the Juubi rebel against Madara? I was also thinking of that distinct possibility. The Juubi was incomplete by the time that Obito took possession of it. Shouldn't it be a problem for Madara as well, especially since controlling the Juubi isn't easy. Well let's see what happens.
Also about Naruto being the reincarnation of the Sage. I saw once a thread about how this OP said that Sasuke was the reincarnation of Hagoromo Otsuki, Naruto being the reincarnation of the Juubi, and Madara being the reincarnation of the Elder Son. Is this a possibility, too?