This would be as fantastic as it is unrealistic. Every game that trys to simulate wars, political intriigue, regligious conflicts etc. does this on an accumulated level (like Mount & Blade, Total War, Civilization etc.) On the individual level of NPCs in a RPG I don′t see this possible with current AI development. First every NPC needs to "live" beeing driven by hunger, thirst, lust for power, striving for wealth etc. Then all of them needed to implemented in a social-economic system which would need a kind of "Meta-AI"
What we would need is not AI or Radiant AI but "A Life" ...
But such AI layering is most definitely possible, there's no reason not to have Meta-AI's as you put it. You'd have the layer of Radiant AI (No longer leashed because the developers are afraid of their NPC's going crazy, and those AI's would be governed by a Legal AI, constantly balancing the system to prevent people from going on rampages or guards from losing their minds and slaughtering villages and each other because of a misunderstanding from an accidental friendly fire mistake. Then you have the AI of the cities, ran almost exclusively by the local ruler, but with a sub AI, encouraging mild sabotage, intrigue, and political infighting among the local royalty to change the ruler, I say mild for the same reason, the point being to always have such infighting, but rarely have consequences-such as overthrow or assassination (I say rarely, but occasionally things can happen, and particularly with a friendly nudge by the players). You then balance this out by a trade AI, that runs all the merchants and their networks, and then they interact dependent on the city states. The local rulers (Namely the most influential NPC in each AI system), will determine the qualities of each meta AI from conservative, to radical, to peaceful, to violent, from ineptitude, to skill, to gullibility, to wisdom. As such most of the AI's will remain relatively intelligent, as the most powerful AI will tend to be the most intelligence, sort of natural selection for the game.We finally extend a sort of civilizations style AI to run the whole map, making deals, bartering, technology, arrangements, marriages, projects, and alliances. The last and least important AI will be the one with influence only in one case, and it will be the combat or war AI, which only turns on when hostilities arise in the latter AI, and then it will be focused on ending conflict quickly to make these wars as uninvasive as possible, but still allowing conflict, war, battles, and the occasionally shift in power through conflict. Such layering is precisely what drive Civilizations, and it could be extended down to the individual NPC level.