Hm, let's see.
Worst to best:
1. Tobirama
2. Hashirama
3. Hiruzen
4. Minato
5. Tsunade
Tobirama made the worst mistakes, and they're pretty big:
1. Edo tensei
2. Segregated the Uchiha even though he knows their hatred can cause them to get angry. (Should've just left them as all the other ninja, just ninja).
But he also was doing the best for Konoha. From one to ten, he's a 3/10.
Hashirama:
1. He left Madara alive. He tried to fix it later, but he didn't.
2. He also gave power hungry villages biju that screwed up his own village.
He tried to make up for leaving Madara alive by killing at the Vote.
He tried to make the biju peace offerings. He failed though.
But he also united the uchiha clan and senju clan, among other clans, formed Konoha, and protected it the best he could.
6/10 for a leader.
Hiruzen made the most mistakes:
1. Oro
2. Danzo
3. Didn't fix the segreated Uchiha clan.
4. Uchiha clan massacre
But he tried I guess. He also had the longest reign as Hokage, so we have to take that into account as well. He's still only a 5/10 though.
4. Minato:
The only thing he did wrong was sealing the Kyuubi into his own son. But he did it for the village's sake. I mean fighting Obito+Kurama is pretty difficult afterall.
7/10.
5. Tsunade:
Despite being the weakest Hokage, she is in fact the best Hokage. The only thing she did wrong was training Sakura. She almost did wrong about Nawaki and Dan though.
She saved many people against pein, she healed Kakashi and Sasuke from their comas, Lee was saved, she trusted Naruto into bringing Sasuke back, she unlike Hiruzen actually tried to kill Orochimaru, and was overall a great Hokage.
8/10 for her
