Its almost assured the Juubi will break free. It would be completely anti-climatic to establish this God-like monster, capable of destroying mountains by just swinging around its tails, just to turn around and say "Just kidding, that God-like creature is now just a powerup for a human character".
Plus, look at the facts. Obito is nothing special. He's just a Jinchuriki. Yes, he has insane powers, but thats because the Juubi is so powerful it affects the host like that. Like all Jinchuriki, eventually Obito is going to be emotionally unstable, and the Juubi WILL begin to break free like we used to see with Naruto. And I highly doubt that the Juubi will be friendly with Obito, so theres no chance of Obito being like Bee or Naruto. He will go berserk eventually, and the Juubi's final form will roam again.