A recent developer diary (opens in new tab) details how an upcoming Crusader Kings 3 (opens in new tab) update will change the AI, resulting in more stable realms, and—most importantly for the most pernickety of map painters—less border gore.
For those unfamiliar, "border gore" is the term among Paradox players for when a country's boundaries, instead of being neatly blobbed together (and ideally belonging to their lawful ruler), are fractional and odd. France, but the shape of a giraffe, with a number of its counties belonging to Wales, with an odd little exclave far up North in Norway? That's border gore.
The update, focusing on diplomatic and economic behaviour, will lead AI to prioritise their realm's stability, instead of hoarding gold and leaving their counties fractured to be picked off.
With four new economic archetypes, AI rulers will be biased differently towards whether to invest in domain buildings, their armies, or their war chest. Interestingly though, the AI will also for the first time accept tyranny—the negative opinion a ruler takes for acting unlawfully towards their citizens. Even a Just and Generous ruler will now accept a little tyranny to revoke their vassals' titles to consolidate their own domain. Less rational rulers may risk even more.
It looks to be an interesting update for both war-oriented players and roleplay-oriented players. Increased realm stability from your enemies should be a boon for players who have complained that it's too easy to min-max your way into becoming a super empire—and who want to murder their way into inheriting a non-giraffe shaped France.
I'm personally intrigued by the kinds of stories of revenge and allyship and generations-long grudges that will be brought about when land disputes involve thoroughly built castles, and or when a well-liked neighbour I was befriending vassalizes a shattered realm before I can.
As a substantial overhaul, the AI update will be part of the upcoming 1.7 update, which doesn't yet have a date attached. Perhaps we'll find out more at PDXCON in September, but for now you can read the full details on the Paradox Forum (opens in new tab).