Oh my god no
First
demographic has nothing to do with content. They are publisher terms to help advertisers and retailers know the target audience. Seinen means the magazine has ad's for whiskey and cars, rather than video games.
Content means fuck all. K-On! is seinen, despite having no objectionable material, adult themes, complex ideas, violence, or nudity. It's seinen because otaku between 15 and 35 are magazines target audience.
Demographic is not a detriment to popularity. St. Young Men, from an obscure semi-alternative seinen magazine, sells almost as well as Naruto. Kimi ni Todoke sells as well as Naruto, despite being shoujo. Already popular, a recent movie and anime have turned Uchuu Kyoudai into one of the hottest manga in Japan. Without a new volume, all previous have returned to the Oricon charts.
That being said, Naruto is to indebted to shounen tropes and stereotypes to even be discussed in this manner. Look at this weeks chapter: Zombie Itachi defeated Kabuto using a previously unknown, secret sharingan technique, never mentioned before this fight started. Virtually every cliche of bad shounen has been used in the space of one fight. A beloved character returns after seemingly dying, complete with a change in personality. A previously unknown, super secret, forbidden technique of an established super power is introduced specifically for a single fight. A character with nothing to lose sacrifices everything to defeat one of the last remaining villains. If izanami is only used one time, in this fight, than
every bad shounen cliche will have been used in this fight. Nor is this new for Naruto. Every new arc requires training, a new, a power up is needed to defeat every enemy, and every power up is novel, completely unexplained previously.
Kishi tries very hard to explore deeper themes and has failed miserably. Compare his handling of the Uchiha massacre to Ishvalan genocide and civil war in Fullmetal Alchemist. In Naruto, one little boy is left seeking revenge. Yet the consequences of slaughtering so many innocents is never explored. In comparison, the trauma of the Ishvalan War is ever present in Fullmetal Alchemist. The survivors huddled in refugee camps, the lone man seeking revenge, the divisions and prejudice left in society. Many of the protagonists of the series were guilty of taking part in the genocide. All are depicted to harbor some degree of guilt, symptoms of post-traumatic stress disorder, and anger directed both inwards and outwards. The government who ordered the massacre is the primary antagonist in the series.
The consequences for other "deep" themes have never been explored. Assassination is part of the job, world peace as only a teenage would imagine it, and genetic engineering without any repercussions. Has there been any negative effected caused by shodai genes? Sure Orochimaru was depicted as "bad", but did his experiments have any consequences? No, the themes explored in Naruto are superficial only. This is not a complex, multifaceted series that explores great themes in a complex, adult manner. If that is what you are looking for read Blade of the Immortal or Fullmetal Alchemist. At it's peak Naruto was little more than an above average kids manga, never more, and now frequently less.
---------- Post added at 02:12 PM ---------- Previous post was at 02:10 PM ----------
Those are not Kishi's themes, they are Jump's. "Friendship, Ambition, Achievement" is the magazines theme. Make friends, set goals, work hard, and achieve them. Naruto's stated goal was to be hokage, then to achieve world peace and become hokage. Making friends with previously hostile characters is key to achieving those dreams. By leading the alliance to victory world peace will be achieved. While he may not become hokage by the end of the manga he has become strong enough to achieve that goal when he is old enough.