Naruto is a part of the Big Three, and it has been one of the most popular manga series in the last few decades. One thing that separates Naruto from the other two members of the Big Three is the number of deaths that take place in the series.
Both Bleach and One Piece have fewer deaths than Naruto. While character deaths are certainly important to a series, there are many fans who firmly believe that Masashi Kishimoto did not hold back when it came to killing off characters. Due to this reason, many of the deaths felt pointless as they did not serve any real purpose.
6 Neji Hyuuga
Neji Hyuuga was hailed as a prodigy of the Hyuuga clan. He was a strong favorite to win the Chunin Exams, but he ended up being beaten by Naruto. Neji's loss to Naruto opened his eyes and he began to live more freely. The fight also affected his way of thinking, and he began to train harder than ever.
By the second part of the series, Neji had become a jonin, which is not a small accomplishment by any means. He was involved in some fights before he was finally killed by an attack by the Ten-Tails. The attack was not unavoidable and considering Neji's skill, he could have easily deflected it with his techniques. The purpose of Neji's death was to bring Naruto and Hinata closer to each other. While this may sound like a good reason, it seems totally unnecessary to make a good character die just to promote romance.
5 Jiraiya
Jiraiya was a member of the Legendary Sannin, and he was considered to be one of the best ninjas that the Hidden Leaf ever produced. Jiraiya's purpose was to find the "Child of Prophecy" and train them to become the person, who would save the entire world. After many failed attempts, Jiraiya finally met Naruto, who would make the prophecy come true. Jiraiya trained Naruto for a long time, and during this period, the Legendary Sannin taught him about other important things such as world peace.
When Jiraiya invaded the Hidden Rain, he had to fight against the Six Paths of Pain. In the fight, Jiraiya suffered a lot of injuries, but he could still have run away. The only thing that was holding him back was the thought of Naruto back home. Jiraiya wanted to leave a legacy behind, so he sacrificed himself, but this could have seriously backfired if the Hidden Leaf hadn't figured out the secret message. It would have been much better if Jiraiya had stayed alive and helped Naruto to fight Pain.
4 Madara Uchiha
Madara Uchiha is one of the strongest characters in the entire series. He was manipulated by Black Zetsu into believing that the Infinite Tsukuyomi was the only way to attain peace. Madara made an elaborate plan to ensure that he would be reborn to put the world in a perpetual genjutsu.
Once Madara was reanimated, he managed to steal the Rinnegan from Obito and became the jinchuriki of the Ten-Tails. By amassing so much power, Madara was able to defeat almost the entire Shinobi Alliance. However, he was betrayed and killed by Zetsu, which eventually led to the rebirth of Kaguya Otsutsuki. The problem with his death was that Madara should have been the final villain because he had received the proper character development, and his motives were explained.
3 Shisui Uchiha
Shisui Uchiha was a member of the Hidden Leaf Anbu. Just like his ancestor Kagami Uchiha, Shisui was among the handful of Uchiha clan members, who managed to break the "Curse of Hatred." Shisui was famous for his Body Flicker Technique, which earned him the epithet of "Shisui of the Body Flicker." Shisui also possessed the Mangekyou Sharingan, which granted him access to Kotoamatsukami, one of the strongest genjutsu.
Danzo was extremely worried about Shisui and his power, so he decided to steal his eyes. Danzo succeeded in getting one eye, but before he could steal the other, Shisui ran away. Instead of going to Hiruzen and telling him about what had happened, Shisui decided to kill himself, which doesn't make any sense. If he had gone to Hiruzen, it is possible that he would have taken action against Danzo.
2 Minato Namikaze
Minato Namikaze was the Fourth Hokage of the Hidden Leaf. He became very popular during the Third Great Ninja War, and his heroics earned him the position of the Hokage. Even after becoming the Hokage, Minato still had a lot of room to grow. Sadly, his time came to an end when Obito attacked the Hidden Leaf along with the Nine-Tails.
The attack resulted in the death of Kushina Uzumaki and countless other villagers. Minato managed to defeat Obito, but the main cause for concern was the Nine-tails. At this point, Minato made the decision to sacrifice himself to save the village. Minato used the Reaper Death Seal to stop the rampage of the Nine-Tails. This was of course an emotional decision, but Minato didn't have to sacrifice himself as well. He could have lived and stopped the Nine-Tails by using some other method.
1 Nawaki
Nawaki was the younger brother of Tsunade Senju. From a young age, Nawaki dreamed of becoming the Hokage, but his dreams came to a screeching halt when he was killed by an explosive tag. He died moments after Orochimaru complimented him and his spirit. Nawaki's death served no purpose apart from traumatizing Tsunade. He could have been used as a supporting character and as one of the last known Senju, he definitely deserved a better fate.