I highly doubt that Naruto will go the way of Dragonball, mostly do to the fact that Kishimoto is a big fan of Akira Toriyama and more than likely came to the conclusion that the reason why Toriyama isn't doing much akin to Dragonball Z anymore, as to what happens when you turn your series from comedy to Action/Martial Arts.

As for the Naruto/Sasuke fight: Most of the really big fights are done by a differen't animator. I'm not sure what his name is, though....