So, I've played a game in the Finland region (starting as Karelia) from 867 to about 1130. I must say, the game has improved a lot (assuming CK2+) in some aspects since last time I played, but I also saw some problems. I'd like to share some feedback from my game in case it's useful.
First, AI countries have huge troubles transitioning to more advanced government type. Right now, the situation is as such: I am a Finnish Orthodox kingdom spanning from most of present-day Finland from the north to Courland, Novgorod and Samoyed lands in the south and east. There are other major kingdoms that have converted from paganism: Sweden and Norway (Catholic) and Muscovy, Kiev and Volga (Orthodox), along with the Hungarians of course (also Catholic). Neither of them have gotten out of Tribal government yet. Only a few smaller realms have transitioned to feudalism (a single duchy in Perm, a single county in northern Norway, and similar such extremely small countries). Larger realms seem to have trouble getting the necessary Tribal Organization due to constant revolts. I checked Sweden before I quit for the day: it's at Medium tribal organization. For an AI country, getting 2000 prestige and not having Tribal Organization rolled back by rebellion is a steep achievement, the more so the larger the realm is. I propose that AI countries should be given a "helping hand" with feudalization, either by cutting the prestige requirements (by 50%, perhaps), by reducing the Tribal Organization requirement for feudalization to High/Medium after certain cutoff dates (or otherwise getting some bonus, perhaps after 1000 or 1100, that helps them upgrade), or maybe both. I can playtest if necessary, though I don't know how to make such changes myself (or I'd already have experimented with it).
Second, the raids. Oh man, the raids. They're really frustrating. I'm not sure who can raid at this point, but it seems like every Norse individual, vassal or liege, pagan or Christian, seemed to be able to raid me. Only once they went Swedish and Danish did it seem like they stopped. At any rate, it made for an extremely frustrating experience with all the raids. I don't suppose anything can be done to either lessen raid frequency or make vassals or Christians not raid?
Thirdly, the council mechanics introduced with Conclave still seem a bit unpolished (vanilla's fault), but especially Glory Hounds. They constantly block warfare against weaker realms because "it wouldn't bring glory", nevermind the fact that there are plenty of sensible wars against smaller realms that nobody would oppose. I really don't know of any ways to fix the council mechanics, I'm just inquiring if the CK2+ staff have any plans of poking the Conclave mechanics or if you guys are just hoping for Paradox to clean things up. (Edit: A simple improvement would be making Glory Hounds' war decisions be "swayed by the diplomacy of other voters" if the target isn't glorious enough, instead of them just simply refusing to poach weak targets. The idea of Glory Hounds is still stupid, but such is life.)
Fourthly, adventurers. This is a huge problem IMO. Adventurers seem to have a constant strength of about 5k men, give or take a thousand, consistently throughout the timeline, regardless of target strength. For a small realm, a 5k stack is an insurmountable obstacle that pretty much just presents an automatic game over or "here, you will now lose the best duchy of your realm, there is nothing you can do about it - oh, and the 5k stack is going to stay after the war and it'll be used to dismantle the rest of your realm every time the truce expires". I only managed to survive the adventurers in my game due to abusing tributaries and, in some cases, some really buggy behavior that made my warscore suddenly go to 100% without a fight. (I can't even begin to think how I'd debug that. Probably a vanilla issue.) Similarly, however, the hosts do not seem to rise much above 5k in strength against larger realms. For the Byzantine Empire, for the Andalusian Sultanate, or even just for my modest Kingdom of Finland as it stands around 1130, such hosts are just an annoyance. Wouldn't there be a way to make adventurer hosts scale more strongly based on target strength? Because I feel this is a huge issue that really ought to be fixed. Perhaps the biggest problem in this post as far as playability is concerned.
Finally, the Hungarian names are borked as ever - I was thinking, would anyone on CK2+ be interested in me submitting an edited version of the cultures file with a list of better, more thematic Hungarian names? For example, "Gazsi" is a common nickname for (usually Roma) men in 21st century Hungary, not the 11th century. In general, the Hungarian name list contains a ton of nicknames and modern names, while others are just flat-out misspelled. I know that things like this are probably not high priority for the mod staff, but if you do believe that I am able to make a better list (I am Hungarian, after all) then it's not like it'll cost you anything to accept such a contribution, which is why I thought I'd ask.