I always thought the overall moral of the series is that power gained by hatred is worthless, and not nearly as powerful as power gained from the desire to protect someone or something.

-Gaara, after being taught this lesson, become much more powerful with the "super/uber dense Shakuku sand" or whatever that was.

-Haku was more powerful than Zabuza because he was protecting Zabuza.

-Naruto (i don't really have to say anymore about Naruto that everyone doesn't already know)

-3rd and 5th Hokages (Tsunade becoming stronger after she accepted the position)

-Even Sakura with that part where she cut off her hair to protect Naruto and Sasuke (not as big though)

-Every curse seal guardian has lost to someone protecting Leaf or at least the intention of the mission.

The whole business with the curse seals is all about not letting yourself be absorbed by hatred. Especially with the whole 'no further development' concept.

Sasuke will probably win or if not, at least run off. Oro can't take Sasuke's body for 3 years and Sasuke will end up learning the hard way that hatred doesn't mean more strength. Even Itachi doesn't give into his hate, he just kills people to test his own strength (I assume he has nothing against them personally).

Here's hoping a new story arc will actually open up this year !!