Several more suggestions to put on the table for the Autonomy Faction (AF), grouped into two main topics (the first of which is perhaps more boring but I think important):
AFs are currently disabled for duke-tier titles (kingdoms and empires only). I think it should be activated for dukes as well, especially if military and economic cooperation outcomes are altered in the way for which my previous fervent suggestion/critique suggests would be more optimal (i.e., do not try to artificially discourage count-vassals-only gaming and instead let the system work naturally and fairly through blanket bonus modifiers applied to cooperating AF members' sub-realms rather than just their capital [demesne] county). Not only does this put autonomy pressure on the whole realm rather than just the top liege or vassal kings (a rare sight, in practice), it adds the extra flavor and fun of managing your AF when you're a duke (or a superduke, especially). It would also add another element to strategy when managing realms with the full feudal hierarchy in place due to stacking modifiers from your vassals' happy AFs, if you should be so lucky (technically neutral vassal AFs, but in my experience where I'm managing realms expertly, they either are happy but never do anything about it or they are neutral and cooperate, the latter of which is ~95% of the total outcomes I've seen).
I realize that the negative outcomes relating to repealing crown laws would have to be disabled in the duke's case (easy enough, just do what the code already does when there's nothing to repeal-- lower obligations). Also, I think more thought would have to put into what kind of challenges and boons dukes will encounter that kings won't necessarily, and thus probably some of the mechanics would need be adjusted for duke AFs. Indeed, Meneth, it is possible that you simply limited it to king- and empire-tier first to get it stable and balanced and left the possibility of duke-level AFs for the future. Well, in that case, I do think it should be queued-up. CK2+'s Princely Faction still applied at the duchy level, which was a lot of fun. [The other factions were just a distraction to me.]
Duchy stability would not receive any dramatic hit, as though they must play count-vassals-only, they only have a few vassals to manage, which is the crux of why the so-called North Korea Mode totally fails-- scalability. Since they are forced to only have counts as vassals, though, this would put more pressure on great-great dukes. Admittedly, it would be better if the AF had more negative outcomes which actually could encourage direct splitting of the realm in that case (demanding a secondary duchy title, e.g., the new holder of which would be already landed within its de jure boundaries and awarded by an AF election using opinion_diff = { ... as_if_liege = yes }).
The Duke of Aquitaine in 1066, e.g., would be a lot less likely to successfully force France into elective and then end up effectively forming the Great Archdukedom of Aquitaine (rather than the kingdom) after he inevitably wins his independence, despite having sufficient counties, gold, and piety to form the Kingdom of Aquitaine (?! Gavelkind, why must you still break that AI's brains?). Basically he needs to be nerfed by default, something that the AF would likely assist in that case. Besides, don't you think his half of France wants autonomy too? Why don't they get to join a faction to attempt to do so like their duke counterparts in the north of France can? What is special about the 'duke' title that would make holders of it immune to vassals that prioritize autonomy while kings are not immune to this? If we care about punishing so-called North Korea Mode, why are we not punishing ultradukes for having 15+ count vassals as they expand?
Most importantly, though, the AF adds an extra element of fun to playing. I want to be forced to deal with my [intrinsically] autonomy-focused counts, especially as I go through the growing pains of moving from a weak duke or count to an ultraduke on the verge of usurping/creating a kingdom. I also want to be commended or gifted by my vassals for a change; maybe that might happen if I have enough happy ones and am exposed to AF meetings no matter what tier my character is currently playing. Since I know the AF still has a lot more potential than what it even currently brings to the table, I especially want to be able to interact with my vassals/liege via an AF at all tiers, because I know that potential will get increasingly fleshed-out and balanced in time.
It is truly rare for me to start at the king- or empire-tier. It usually takes a long time (though not long enough) to make it to that tier, and I don't get to play with the autonomy faction at all in the interim. I'm pretty confident that I'm not alone in the like-to-start-small camp, so there are a lot of people spending the vast majority of their game time without ever managing an AF.
Speaking of managing AFs (on to the second aforementioned topic):
We need to implement more ways in which the mood of the AF can be boosted temporarily, either short- or long-term, rather than modeling it as a purely stateless, static, reactionary function of laws, traits, and opinion. For one, there could be temporary mood swings.
They might be based upon victorious wars, provinces converted to the "realm religion," recent succession (bad), crusade victories/losses (mega-wars with a lot of glory), realm-wide tournaments (if only they'd live up to their calling-- not quite there yet) for a minor bonus, a bonus for every internal revolt crushed, bonuses for consecutive years of peace up to some cap, a malus for every instance of raising a vassal's liege levy (per-vassal, so think about whether you really need to Raise All Levies or not)-- basically, temporal modifiers derived from the actual successes and failures of your realm as well as the autonomy-impinging and autonomy-enabling actions taken while maneuvering your realm through those successes and failures.
These kinds of AF vote modifiers would also improve the player's ability to causally link his/her actions as a ruler and general outcomes of the game to the mood of the AF, something that currently suffers from too much transparency and (relatively) arbitrary / static modifiers (often things you just can't do anything about and aren't very visible at all-- not even with the help of a slide rule and the AF scoring spreadsheet most of you've probably seen by now), and this more direct correlation of in-game actions and outcomes to AF meeting moods and their chosen courses of action would greatly improve player satisfaction.
Further, all these temporal modifiers encourage the player to actually achieve (or fail) at various such things essentially all the time in order to prevent rebellion due to the, e.g., more leeway granted toward CA due to a tradition of successful temporal achievements-- micro-ambitions to always be multitasking and for which to be preparing, driving the player to always have something to do and a reason to do it, greatly improving player satisfaction as well.
In other words, we can make the AF work more like it would in the real world through temporal modifiers. Not only would we improve the gameplay / satisfaction factor [more], but I'm convinced that temporal modifiers are required to balance the AF and free it from being a repetitive function of the same things that cannot reasonably be changed (except for maybe removing title revocation, once in your ruler's life), assuming you already play to maximize opinion of direct vassals (obviously).
Indeed, we can even get very deep and make the temporal modifiers all per-member of the AF so that different types of temporal stimulus will affect diversely-disposed members differently on a case-by-case basis. Members with, say, a lot of zeal will care more about religious successes that they helped their liege, indeed at least through their implicit cooperation, achieve (e.g., winning or even participating in a victorious crusade is probably going to give the liege ample leeway to squeeze some necessary autonomy from those members in the process and for some time afterward, but a humble, slothful, cynic that is nowhere near the infidels is probably going to be only slightly fazed by such a glorious temporal outcome).
If we went to this level, then you'd really need to cooperate with your vassals in a greater sense. Regardless of your own ambitions, you'll need to find the time and resources to pander to your particular, dynamically changing set of vassals' ambitions/concerns at all times if you expect to have the authority to push your own agenda as well. This is how Charlemagne, fief by fief, conquered and built arguably the largest, particularly in terms of wealth, feudal demesne in Christian history before even hitting 50 (died in his late 70s). He knew his many, many vassals well, and they were willing to get behind him, fund him, and man his armies because he reliably, successfully fulfilled their concerns/ambitions as he went, and even when the cycle of successful conquest was over and the spoils all distributed (or in Charles' vast demesne), his realm was fully stable during his lifetime, with what we'd now call high crown authority no less, because he continued to take into account actions that would please the majority of his vassals. For example, one might argue his acceptance of being crowned the first Holy Roman Emperor was, while stroking his own ego no doubt too, in spite of his personal agenda or beliefs (his lifestyle clearly indicated that, though he was pretty much a True Christian Knight himself, he personally promoted progressive policies / behaviors among his court and family that were strictly forbidden or even considered heretical by Rome). He wrote in his diary that he was quite reluctant to accept, shocked when the Pope presented the opportunity, and concerned about the political effects of acceptance both outside of his realm (the ERE) and for his descendants (cynical regarding the idea of an official "holy" empire, let alone being personally elevated above all men). And then he went ahead and just decided to accept anyway. Could the thought "What will the people that matter most in my kingdom think if I turn down an official blessing of my realm, above all others holy, from the Roman Catholic Church? I've no choice, right?" have occurred to him?
Yes, that was a lot about Charlemagne. The whole darned point, though, is that vassals are never sheep; they all want autonomy. If you don't demonstrate that you care about what they do too, if you don't exploit that which you have in common with vassals' general disposition and ambitions, if you don't even take one for the team sometimes and outright pander to, say, a bunch of overzealous vassals (say, when you're a cynic mostly concerned about securing your legacy for your sons and consolidating your demesne) and make sure you actively convert provinces and consistently keep pushing-back the Moor every 10-15 year so that those vassals are fulfilled-- all temporal maintenance outcomes that cannot be trivially covered by the current way faction voting is scored, then you should never be able to accomplish your own personal ambitions, because your vassals will rise up and take everything away from you, unsatisfied by your rule, and not achieving the level of autonomy they think appropriate for what you actually do for them (until, finally, it's abdication time).
I have some ideas on how to implement temporal modifiers per-member of the AF (which factors then into each member's vote). It's definitely doable, especially since even 2-3 such modifiers would make a serious difference. We really want to reinforce a causal link between player actions, aside from the mundane stuff like managing opinion (which is a small deal anyway in the vote scoring), and how their vassals choose to interact with them. All this stuff _would_ work with an opinion modifiers implementation + some scaffolding, but opinion modifiers are overloaded with junk unfortunately. I've also some ideas on how to generally find the common ground between liege and vassals in a way that isn't transparent before taking the actions that would please your vassals. Think: Knights of The Round Table.
But I've written enough for now; I think that's enough AF input for a couple weeks. This is how much I like PB's budding new feature, the Autonomy Faction, and how much potential I believe it has.