I don't think the explanation to how naruto can now control the 9tail is adequate. He's 4th's son, good for him, but does it bestow some latent power that we yet know about? If yes, cool stuff, if not then the connection is rather tenuous. "Oh I have to live up to my daddy's expectation and now I can control 8-9tail perfectly, despite the fact that it's THE most powerful tail beast around and my daddy, one of the most famous ninja of all time, died defending the village against it."
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