After watching it, all i can say this series is not perfectly written, its looks like they go too much improvisation and change of scheme all of the sudden.
and somehow they insist to put too much anime element in the series and it seem the writer can't let go of one character easly.
They just simply want their groups travel together like one piece, having naruto sad backstory, stronger character keeps apearing that remind us of dragon ball, every character rely on secret skill that often to be seen in saint seiya, and they make the series having short amount of episodes like sir Watanabe masterpiece.
In the end they make this anime is too much predictable at the moment.
So please don't call this "the best anime ever"