-The "main quest" is pointless. No rewards and barely provides the player a pat on the back for completing it, despite how difficult and time consuming it is. Warband had it right.
-Sieges are gross. The settlements have massive advantages, unless you own them, and you can't starve them out. Imagine my disgust when I brought an entire year's worth of food and found out that only the garrison will die from starvation. The enemy lords, however, seem to be able to hang out indefinitely with their armies intact.
-The ability to craft weapons is cool. However, to get the materials to do so you have to either spends tens of thousands of gold on weapons to dismantle them, or waste your skill upgrades to get the right 'perks' at the expense of being able to unlock parts. Even if you get the skill as high as it is possible to get it (somewhere in the 400's), there's still a chance you have some locked parts. And to top it off, you can't make armor.
-Limited customization with of clan emblem. Seriously, I've seen single dev games with better customization options.
-Limited options to gain land. Usually requires tons of cheese. It's cool that you get to choose the bannerlord though :p
-Criminal stuff is incomplete and useless. Becoming a bandit is a dead-end option. Fighting criminals in a city will increase your relations with notables (relations which will go up anyway) but decrease your relation with whoever you're attacking. Great for locking off recruits from yourself for no good reason.
-The only way to prevent robber-barons is to kill them, which can lead to rebellions because their relations with lords that have joined you/notable under your control do not deteriorate at all. Even if they perform actions which would normally cause relationship deterioration.
-Marrying people off has no point. Neither does marrying into a family. I usually marry Ira for ****s and giggles, but it has never awarded me any sort of advantage other than having her in my party. Even if Rhagaea dies the nobles vote for the next ruler, which likely won't be you or Ira.
-The skills and perks are broken. Leveling is so slow that by the time you have the skills to actually do something cool (without cheating or cheesing), your character is at risk of dying from old age. The only skill that allows a reasonable grind time is smithing.
And now for the meta things!
-The wiki is less helpful to learn about game mechanics than reddit threads. Hell, the actual wikipedia page might be more helpful.
-This game has been in development for ~12 years (EA began in 2020, 10 years after dev began) with more people developing it than Warband, and it doesn't even have as much content as Warband. To me it feels like every step forward the devs take, they take two steps backward trying to prevent 'snowballing'.
-They seriously charged 49.99 for this.
/rant