The Hokage are known to be some of the strongest people in the Naruto world. While all the Kage in the story are extremely impressive, those from Konoha have always shone more than the others and are, thus, respected more than the other Kage.
That said, the Hokage of Konoha have also made some terrible mistakes during the era of their reigns. Some of these mistakes were massive enough to shape the course that the entire Shinobi world took, and others destroyed generations of Shinobi themselves. Konoha certainly has not been led by the best of people at all times, and some of the mistakes that its leaders have made have been truly terrible.
Hiruzen Failing To Protect Naruto Uzumaki. Naruto Uzumaki is the protagonist of the story, and he was born on a fateful day when Obito and the Nine-Tailed Fox attacked Konoha. Both of Naruto's parents ended up dying while protecting the village, and he was entrusted to the Third Hokage for the sake of protection. However, Naruto was badly taken care of as he grew up. The Third Hokage isolated him for the most part, only seeing him when he gave him his monthly allowance. At the same time, Naruto lived a horrible life, as was evident from the fact that he was living off of expired food.
Tsunade Failed To Save Konoha
Protecting the village is the primary responsibility of any Kage, and when push comes to shove, these Shinobi are whom the people of the village look up to. For a Kage, there is no greater task than defending the citizens of the village, all of whom are their families.
When Pain attacked Konoha, Tsunade was carefully trying to save every single life in the village. However, she did not have enough strength to save the village as well. Pain utterly decimated the entire village and led to countless deaths. While Tsunade did save quite a lot of lives, she was not able to protect everyone, and that in itself is a failure of sorts. That said, the majority of her reign was very good, and she is among the best Kage seen in the story.
Hiruzen Failed To Save The Uchiha Clan
The Uchiha Clan fell victim to an operation that saw them being eradicated entirely shortly after the events of the Third Great Ninja War. This event was orchestrated by none other than Danzo, an elder of the village. The Uchiha were planning an uprising because of how they were treated. Being ostracized and looked upon as lower citizens, the clan looked up to Fugaku to lead a peaceful revolution.
However, before this event came to pass, Itachi wiped out the entire clan on the orders of Danzo. The Third Hokage, while not involved in this incident, did not do enough to protect the Uchiha. He did not do enough to give them safety and, eventually, paved the way for their demise.
When Hashirama Failed To Protect Children
Hashirama was one of the most iconic people in the world of Naruto. Before him, the concept of villages didn't exist, and it was only thanks to his efforts, along with those of Madara, that the concept of a shinobi village came to be. Hashirama created the villages to avoid children being sent to war and fight the battles of adults. He wanted a peaceful place for everyone where love and respect were shared, and wars would not have to be fought.
Although Hashirama took the first steps towards achieving peace, he was unable to stop the wars, as was seen later on in the story. He ended up fighting in the First Great Ninja War, and that is also where he died. What's more, children continued to be sent to these wars and, as such, this was a failure on his part.
Tobirama Let Down The Uchiha
When it comes to hatred for the Uchiha, nobody can overtake Tobirama. The Second Hokage absolutely despised this clan, so much so that he convinced his brother not to let Madara become the Hokage directly. What's more, he instilled the mentality of Uchiha being dangerous among the next generation, and people like Danzo are a direct result of his teachings.
What's more, during his time as the Hokage, he ostracized them and, to quell any revolution, he put them in charge of the Konoha Police Force. The downfall of the Uchiha Clan was all orchestrated by him, and he is the Hokage who failed them the most.
Hiruzen Couldn't Hold Orochimaru Responsible
Orochimaru was one of the most dangerous villains in early Naruto. He sought to destroy the village and, to achieve this, he would go to any lengths. Orochimaru caused a lot of damage, not just to the village, but to many innocent people as well. He was known to be experimenting on humans and killing them just to advance his goals.
He was what could be termed a 'mad scientist.' When the Third Hokage discovered that he was kidnapping people and conducting experiments on them while they were alive, he could do nothing to stop him, just because he was his teacher and had a soft spot for him. Countless lives could have been saved had the Third Hokage taken action instead of just letting him escape.
Minato Couldn't Stop Obito In Time
Minato Namikaze became the Fourth Hokage of the village following the events of the Third Great Ninja War. While Minato was a very powerful Kage, he still had moments where he couldn't do as much as he should have. One of the prime examples of that is when Obito Uchiha attacked the village in the Third Great Ninja War. Leading up to it, Minato failed to rescue Obito Uchiha and save him in time during the war. Similarly, when Rin was kidnapped, Minato failed to rescue her in time as well. This eventually led to Obito falling down a dark path, which led to the attack on Konoha on the day that Naruto was born.
On this day, Obito faced off against Minato, and even though the Fourth Hokage stopped him in his tracks, he was not able to put an end to him right there. Furthermore, the Nine-Tails ended up killing multiple Konoha shinobi as well as civilians in its rampage. As the Hokage of the village, it was the responsibility of Minato to protect all these people, but at the end of the day, he failed to do that. He also ended up losing his life in this attack at a very young age, which was disappointing considering the talent that he had.
Naruto Couldn't Stop The Threat Of Kawaki
Naruto Uzumaki became the Seventh Hokage of the village, but just like every other Kage, he too had his faults. In the case of Naruto Uzumaki, this fault stood out especially during Kawaki's development. Naruto's bond with Kawaki was incredibly strong, to the point where he eventually ended up adopting him as his own son.
However, Naruto failed to instill the right values in Kawaki, which eventually led to his own son sealing him away in the dimension of Daikokuten while he went after the life of his other son, Boruto Uzumaki. At the end of the day, Kawaki will come around, but Naruto not being able to instill these values in him in time is what has put Konoha through its worst catastrophe in years.