One thing ive noticed is that the AI never seems to divorce, not really an issue but AI dynasties also die out significantly easier than they ought to.
Should there be either an event or an AI encouragement for seeking 'divorces' on marriages which after say 10 years of being married have not produced a child.
As Historically Annulments are common for unions which fail to produce viable offspring, as thats the whole purpose of a marriage, Catholic marriages being the recognition of the natural marriage of parents bound in duty to the rights of their children so if there are no children then annulments can be easily granted as then its a recognition of a natural marriage that doesnt exist. So theres an story-immersion rationality for it.
But probably more important is the game-play concern of all the interesting dynasties dying out in the first or second generations. Especially the ones you get randomly on castle baronies and then grant some land to only to get that land back twenty years down the line as the AI took a wife too old to get a child from.
And if the AI could just grasp the divorce mechanic and use it when appropriate and legal [probably without the piety requirement which is there to limit player exploitation and is probably too expensive for barons] then the problem would be lessened as to just happen a realistic amount of the time instead of the vast majority of the time.
As generally all the unique dynastied random characters dont make it past the first generation, in my experience anyway, as there's few enough of them around so letting them have access to the same options as the player does and encouragement to use them when appropriate might do to keep them going.
And yes the game calls them divorces, but even in these modern times, alliteration is still important.
Or can the AI already do this and ive just not noticed?