I like how the game has developed. Didn't play for many years, but stashed up all DLCs and just finished a 700 year run (takes a bit too much time to complete, many days literally), with goals vaguely set by achievements along the way. Aztecs disabled. However, there are somewhat bad stability and performance issues toward the last 100 years. Game gets slow, won't save etc. Big performance improvement after quitting to desktop and then back again, so likely memory related.
Progression from tribal county to autocratic empire and the different ways the game plays through each step is great. The bad boy score can be bypassed by letting vassals declare wars externally (here a setting that forbids intraimperial wars, but allows foreign seems missing). However, at some point I snowballed and lost control. Didn't want to disable it because it doesn't require much management from the side of the player, while expanding at a good pace. External/internal fighting gets more attention than fighting the central power. My vassals nearly captured the Frisian coast, with little to no input, but unfortunately the game ended one county short of that achievement.
Also decided to rush the mongols to get the Norse-East. Halfway there's a fast route covered by rivers, but the Ural pass is a deadly retinue killer winter time, and it's very hard to reinforce the area south of the Baikal. The mongols are fast and reinforce ten times faster. With 10 years left at 100 threat rating the additional drawback was that I had to declare world war over Mongolia. I tried to rush them with retinue, but it turned out that gaining score is very difficult, considering the provinces are junk and require forts (which will be razed by looters and 200-detachments), basically you win by capturing their nobles and the capital. But it was just too much work to keep that up with maintaining sieges in Europe, while trying to engage enemies and cover ground in Mongolia. In ten years my Fylkir had accumulated 500 prisoners and an equally formidable kill list. The troops held out for the duration, but eventually didn't manage to turn the score to 100 (heck, it started at -50%, the game seems to give score priority to clearing out home front occupations in offensive wars, which could've been handled separately. Too bad the game lacks separate peace/truce deals). The game is just too detailed too be played conveniently at grand strategy scale.
It's a bit quirky that you have to hold the british isle kingdoms personally to trigger the achievement there (vassals are not enough). Basically find plot -> imprison -> fight -> revoke , but feels very unnecessary.
Odd features like the Horse MD and so on are pretty OK, because there's a rational explanation behind. I just don't like the random ice bear dynasties that act as if they are human. Fellowship of Hel is ok too, a little bit of magic, but nothing that detracts from other semi magical features of the game. Most of it can be toggled on and off in the game rules too which is a plus.