In the Hokage succession of the Leaf Village (Konoha), two individuals are notably recognized for causing significant turmoil within the Naruto storyline. They are the Second Hokage, Tobirama Senju, and the Third Hokage, Hiruzen Sarutobi.
But between Tobirama and Hiruzen, who is the more competent Hokage?
1. Contributions and Mistakes of the Second Hokage, Tobirama Senju

The Second Hokage, Tobirama Senju, made significant contributions to the development of the organizational structure of the Leaf Village, establishing foundational systems like the Ninja Academy, the formation of the Anbu Black Ops, and the Chunin Exam system.
Despite many accomplishments, Tobirama is also known for some regrettable mistakes.

Tobirama rose to prominence during a time of great war, coming from the Senju clan, which had a long-standing feud with the Uchiha clan. This historical conflict led him to harbor suspicion and hostility towards the Uchiha clan, influencing his controversial decisions later on.
The formation of the Anbu Black Ops was intended to ensure the safety of the Hokage in relation to the Uchiha clan, resulting in most members of this organization being Uchiha. However, Tobirama never truly trusted the Uchiha, using the organization as a means to monitor and keep them in check.
Beyond his contentious actions against the Uchiha, Tobirama also created a forbidden technique, Edo Tensei, a jutsu that reanimates the dead.
It is undeniable that Tobirama was a highly skilled ninja. He not only excelled in ninjutsu but also pioneered many powerful techniques such as the Shadow Clone Technique, Teleportation Jutsu, and Edo Tensei (Reanimation Jutsu).

The Edo Tensei technique involves resurrecting individuals at the cost of a living person’s life. How did Tobirama develop this technique? Did he use it during wartime for his own experiments? This remains a mystery.
However, later on, this technique was exploited by Orochimaru, who perfected it. It resurrected both Tobirama and Hashirama, leading to significant events during the Third Hokage Hiruzen’s era. Additionally, Kabuto utilized Edo Tensei to revive powerful ninja from the past, leading to heavy casualties in the Fourth Great Ninja War.
2. Contributions and Mistakes of the Third Hokage, Hiruzen Sarutobi

As the Hokage of the Leaf Village, Hiruzen Sarutobi prioritized the well-being of all Konoha citizens, often interacting with them and addressing their concerns.
However, beneath this friendly facade, Hiruzen’s tenure was not without its dark actions. Allowing Danzo to operate under his command led to significant chaos and future conflicts.

In his role as the Third Hokage, Hiruzen did not take decisive actions against Danzo and often allowed him to carry out morally ambiguous actions. This resulted in the Anbu Root becoming a rogue faction within Konoha’s Anbu, creating immense danger and leading to many innocent lives being lost.
Moreover, Hiruzen failed to effectively resolve various conflicts within the village.

Even though Danzo was a key figure in the Uchiha clan massacre, Hiruzen’s mistake was his indecisiveness in making decisions, which ultimately led to the tragic events against the Uchiha clan.
When evidence of the Uchiha clan’s intentions to seize power emerged, Danzo directed Itachi Uchiha to infiltrate the clan under the pretense of collecting information. Hiruzen merely sought peaceful resolutions, but by the time he realized the gravity of the situation, he had no solutions. Consequently, Danzo ordered Itachi to eliminate the entire Uchiha clan, leading to a massacre that stained the Leaf Village’s reputation.
There was also conflict with the Hyuga clan and the main branch, which resulted in the death of Hizashi Hyuga, Neji’s father, who was sacrificed to resolve the feud.
Additionally, Hiruzen was too lenient with Orochimaru, tolerating his unethical experiments, resulting in many individuals becoming victims of Orochimaru’s ambitions.
Conclusion: Hiruzen is the More Competent Hokage than Tobirama
It is undeniable that Hiruzen was a compassionate and wise Hokage, but many of his decisions were flawed, resulting in the sacrifice of numerous lives. During his time, the instability remained prevalent in Konoha, even affecting renowned ninjas like Sakumo, and leading to significant issues with the young Naruto. Moreover, Danzo’s actions under his command resulted in several controversial decisions and solutions that led to many conflicts and losses.
In contrast, Tobirama, while decisive and pragmatic, made many decisions that had dire consequences. However, they did not lead to as many deaths as those caused by Hiruzen’s actions.