Why do you think he was such a threat as Locutus?

Tactical genius too. Invented his own combat maneuver that is supposedly unbeatable. Weird that nobody else seems to use it.

where they need the next ghengis khan to bring the galaxy to its knees

Or some other Khan

I imagine a fantasy kingdom, that due to a civil war, they decided to have 2 kings, one from each side. they are tethered by death, when one dies the other is executed, they share palace and have to govern together, sharing equal power. and it often results on one of them being a violent warlord and the other a pacifist.

Listen i love your head cannon, but I gotta ask as a casual fan, when did you get the idea hes a psycho? Ill admit im Picard biased because next gen was my first, and the way he pronounces the word "civilization ". But I did always think he was one of the calmer ST captains.

Enders game style.

But one thing is for sure, Picard has no head cannon.