Most Naruto fans only tend to remember the strong characters from the series. These characters are easy to notice because of their special abilities. These characters were either born with these powers or acquired them via training, but it was clear that in either case, the abilities gained by these characters made them strong.
However, there are certain exceptions to this rule. There are a handful of Naruto characters who were blessed with overpowered abilities but were not able to use them to the fullest. These characters had the potential to become extremely strong, but due to one reason or the other, their growth stagnated, and they remained weak. Suffice to say, many fans were infuriated by these characters as they had every tool that would have made them strong.
7 Danzo
Danzo thought that he was the only person who cared about the Hidden Leaf, but with time, it became clear that he was just a bitter person. Danzo did not care about the village; all he cared about was being in power.
Like a coward, Danzo orchestrated attacks on the lives of people who were stronger than him. Danzo's weakness drove him to the point where he readily agreed to be a test subject for Orochimaru. Danzo's right arm was made up of Hashirama's cells, and it was covered with the Sharingan of the massacred Uchiha clan members. Each Sharingan granted him the ability to use Izanagi, which is basically another chance at life. Despite all the Sharingan that he had, Danzo couldn't even beat a young Sasuke.
6 Moegi
Currently, Moegi serves as a Jonin for the Hidden Leaf. When she was young, no one expected her to become a Jonin, so it was surprising to see her become one. In Boruto, it was revealed that she has access to Wood Release, which is considered one of the most overpowered abilities in the series.
In comparison to other Wood Release users, Moegi doesn't have any major accomplishments. She has been on the sidelines for a very long time, and it seems unlikely that she will get any stronger.
5 Hidan
Hidan was a member of the Akatsuki. After joining the organization, he was paired with Kakuzu, and the two of them were called the "Zombie Combo." The reason behind the name was their immortality. Kakuzu wasn't completely immortal; he just had more than one heart. So, he was very careful while fighting his opponents.
On the other hand, Hidan was completely immortal. There was no injury that could kill him, and this made him complacent. Hidan would recklessly charge into a situation and get into trouble. This is the key reason behind his defeat by the hands of Shikamaru. An immortal being like him should have definitely done more to gain power and learn new jutsu.
4 Haku
Haku lived in the Land of Water with his mother and father. Due to the continuous wars that took place in the Land of Water, all Kekkei Genkai users were treated with disdain. When Haku's father discovered that Haku and his mother were Kekkei Genkai users, he gathered a mob and killed his wife.
But, before they could kill Haku, he used Ice Release to kill them. After killing them, Haku met Zabuza, who took him in as an apprentice. Haku was trained by Zabuza to become a weapon, but he still had many flaws. Haku was bested by Naruto, which shows that he wasn't as powerful as he was made out to be. With a rare Kekkei Genkai at his disposal, Haku should have been much stronger.
3 Mei Terumi
Mei Terumi is the Fifth Mizukage of the Hidden Mist. She came into power after Yagura's dreadful reign, so she had to work a lot. Mei's efforts started paying off as she managed to solidify relations with other villages.
As the former Mizukage, Mei is one of the strongest fighters in the village. She possesses two Kekkei Genkai— Lava Release and Boil Release. Both of these abilities are very powerful, but Mei was not able to do much with them. She was arguably the weakest Kage during the Five Kage Summit, and she was not a great help in the fight against Madara Uchiha.
2 Shisui Uchiha
This is a controversial entry as Shisui wasn't technically a weak character; however, given his powers, he was very underwhelming. Shisui had the Mangekyou Sharingan in both of his eyes. He was armed with Kotoamatsukami, which is the second strongest Genjutsu in the series.
Despite all this, Shisui was not impressive in his fights. Danzo managed to catch him off guard and steal his eye. This particular incident tarnished Shisui's reputation as Shisui was considered to be one of the fastest ninjas alive.
1 Shino Aburame
Shino Aburame is a victim of bad writing. While his design is not flashy, Shino should have been one of the strongest characters in the Hidden Leaf. Born into the prestigious Aburame clan, Shino was destined to become one of the best ninjas in the village.
As a member of the Aburame clan, Shino had access to different kinds of chakra insects. Some of these insects were capable of draining the chakra of the target, and their huge number made sure that the job was done in a short period of time. For some reason, Shino was taken out of the spotlight, which limited his growth. By the end of the series, not much had changed about Shino, and he was slightly more powerful than before.