Warbands siege AI was also really wonky and horrible at times (Remember when you could backdoor an entire infantry line and none of them would turn around?). The main reason why they seemed to "work more" is because of the scale of the maps (Being much smaller) and the fact that siege weapons were either ladders or massive walkable siege towers, which was WAY easy to make a navmesh for. But we still could enjoy the whole experience despite this, which I feel is the same for Bannerlord.
Bannerlords siege AI and navmesh is much better with them using other types of siege weapons and cover whilst constantly running around trying to suppliment different areas of the map. The main issue is that the navmeshes on a number of maps doesn't tell the AI that "There are 3 ladders on this siege tower", but instead it tells them that "This ladder on the tower is the fastest and best way", which leads all of your troops to try to go up that ladder. Some Siege maps I have noticed that they use 2 ladders, but the third one is always accidental and the AI tends to actually walk off the third ladder to get to the "quicker and better ladder(s)" according to the navmesh.
I hope that now with snowballing not being a major issue anymore, that they can finally revisit all their siege maps navmeshes and rework how their maps tells their AI on how to navigate walls and ESPECIALLY Siege tower ladders. That's where I've personally noticed the most amount of issues when it comes to the AI. Once they're off the walls and is running around, they tend to easily navigate the city/castle. After they have mostly fixed most/all of them, then they can add in more city/castle maps.
I also know that you guys are scared that the "Early access period is almost over". Yet, you do know they can just extend that period or just fix up as much as they can right now and you know...Just keep fixing and adding in content post launch?
If we all enjoyed Warband so much even with it's sometimes wonky sieges. I think we can still enjoy Bannerlord with it's currently wonky sieges.