The maps we have now were never intended for more than ~20 AI soldiers per player and were likely given AI routes with that in mind.
Is pathfinding actually to blame for the way AI behaves in mass battles though? You can see the same behavior replicated on flat maps where terrain navigation is not an issue.
Furthermore, I'm surprised to see no toggle to force AI to use polearms when most infantry get a free one as a secondary when we've had a blunt weapon toggle since the first M&B. Other videos showed Legionaries ignoring spears even when using defensive formations and the Empire troop literally named after the polearms they are supposed to be using charge into battles with their sidearms drawn. I suspect this might be because, just like in Warband, spears are weak in the hands of the AI - here the problem could be even worse because the infantry just hugs each other.
I get it, unit and polearm simulation is tough, but things were actually *better* at some point. Check out Viking Conquest:
Besides the enemy constantly reforming the shieldwall in the middle of the engagement for some reason (I assume thats why they keep dancing to the side), notice how the AI actually give each other much more space which not only enables them to use their weapon types effectively but also means that adjacent characters in a unit can actually cover each other and prevent flanking - you know, the whole point of a formation. The individual AI might be too passive in the video, sure, but this is something I expected Bannerlord to fix: take the massive tactical advancements introduced by to the game by mods and arguably perfected by VC (which in itself is a mod glorified into a DLC) and build a an individual battle AI that actually uses them to their full potential. Instead we appear to be getting formations from aforementioned mods with an even more spastic AI, which is the only way I can explain shieldwall AI being as broken as it was for as long as it was in the beta (when a few playtests could have identified the issues present, let alone some degree of design effort).
I could be wrong on a lot of these counts as I don't have access to the beta myself, and am only going by the bannerlord videos + my own experiences in prior titles and their mods, but I am yet to find footage or information that addresses this.
idk fam I hope I'm wrong but it sure looks p. f. disappointing