Naruto's watchable up to that point... If it's your first shonen. Otherwise, after you see enough of the genre, you get really fucking tired of training arcs, fighting tournaments, etc. When the hero gets his ass handed to him but suddenly turns around or comes back another time after extensive training, you're not really surprised or excited anymore. Because you know its been done to death. There's a formula and you learn it.
But think about anon. What would Naruto be like if it broke the mold, and was more of an episodic series, with short 10-13 episode story arcs at most. If the show was actually about life as a ninja in the Naruto universe. Keep all the superpowers and shit, but imagine if Naruto was otherwise about down to Earth political intrigue and touching stories about humanity, about the implications of being a 13 year old highly trained assassin employed to a feudal lord. Sure, there'll probably be a formula still yet, but you have to admit, it'd be a hell of a lot more interesting than the FIGHTING TOURNAMENT, BETTER POWER UP, BAD GUYS WANT MY SUPER 1337 H4X POWERS, BETTER POWER UP, MY BEST FRIEND'S CLICHE DARK PAST LEADS HIM TO BECOME AN ANTAGONIST, DIDN'T SEE THAT COMING, BETTER GO STOP HIM FROM MAKING A TERRIBLE MISTAKE THAT HE WON'T BE ABLE TO REVERSE THAT I OBVIOUSLY WON'T SO THAT HE'LL STAY THE BITTER RIVAL CHARACTER AND BE A VILLAIN FOR A SHOWDOWN FOR SOME UNDETERMINED POINT IN THE FUTURE, BETTER POWER UP shit it really is.