I keep seeing these Naruto-related discussions and on each and every one of them, they keep implying or outright saying that Naruto got significantly darker on the second season. For the life of me, I can't understand. Why? How are people coming to this conclusion? First major villain in Naruto was a mercenary who slaughtered an entire class of children. Gaara was a mentally disturbed kid who spent a better part of his life surviving assassinations conducted by his own flesh and blood. Even Sasuke's backstory is truly horrifying and he's one of the sane ones. As for character deaths, Sarutobi bit the dust and it was pretty sad. Yeah, I know Part II had more important characters dying, but Part II also had a larger character roster and a much grander plot so that's understandable.
One of my theories is that people confused "bigger" with "darker". Shippuden dwelled more in philosophies regarding war and true peace, where as Part I was far more isolated. There was a greater focus on the character's personal struggles as opposed to the huge crapstorm that was the Fourth Shinobi World War.
It's funny cause even the guys behind the Boruto manga claim that the series is gonna be much more lighthearted than Naruto, and then they make the first villain post-Momoshiki a child-eating cannibal.