All of them are poor bar Tsunade. They all escalated conflicts and no one did worse than Tobirama - the man literally clung to his past, unwilling to let things go. Poor, skewed, arbitrary, shallow, and cheap as a Leader - all that summed up into a volatile political system that collapsed on its head, didn't thwart conflicts within the village, and surely created the grounds for future generations to gain positions within a military set ups through grotesque exams. No one is worse than this guy.
Hashirama's gift wrapped Bijus didn't deter any political conflicts, it fueled the flames. Hizuren did nothing for Uchiha can and Hyuga branch family, and upheld Tobirama's policies. Minato's rein was fruitless as well. The only person who actually tried to mingle with the general public, set clear bounds for Elders and Root, and paid heed to Village issues was Tsunade. She is a great Leader. I hope she doesn't relinquish her position to Naruto.