But that's the thing, Senjus don't tend to have any in born talents so they tend to work very hard to over compensate by getting into a whole bunch of other things. In contrast, Uchihas tend to lack the capacity to form relationships so they're always irate as though 24 hour gut constipation.
I believe the best Kage would be Muu. A perfectly balanced Kage in, character, conduct, ability, tenacity and strength. Muu appears to be quite emotionally mature while maintaining facets of tactical and analytical intelligence.
Hashirama appears childish, like most Senjus. Which explains their irrational perseverance towards strength and power. Uchihas are the same, it seems. Both appear immature, spoiled and childish. You could classify Senjus as closet narcissists and Uchihas as closet psychopaths.
tbh, it's not the most powerful that matters, but the most reliable, intelligent (both cognitively and emotionally), analytical and rational that matters..... arguably, the most ethical or the one with the most heightened sense of morality is the quality that matters as well.
Balance is key, and maturity is the door to balance.