Honestly the best and simplest solution. Is the opposite of what you said.
Give the general AI + 50 or even +20 Hp and he will be much harder to kill during fights, so the combat last longer. Theres a sub mod for it. And i think it honestly should be by default. The AI is only not suicidal when its a Infantry Unit. Because he is slow, and cant just run and tire himself out like the horse generals do. By the way dont take this as a form of criticism, i honestly would love AI generals to not be suicidal anymore, but i think thats an AI hard coded issue. If im wrong great, but it just does not seem possible on this engine. I just read the thread again and saw you already did. HA well i think your idea is interesting, Anyway to make these Generals stop acting like Banzai Charging units would be great.
Its this Mod
https://www.twcenter.net/forums/showthread.php?792182-Stronger-Generals-Harder-Battles