The problem Armor and AI.
Armor is painfully pathetic in Bannerlord. There is no payoff for spending those hundreds and hundreds of K's whatsoever on armor that makes you 5% less squishy than before.
Archers are absolutely overperforming in Bannerlord. A shortbow would do absolutely nothing to a big chest of lamellar, plate or even mail.
Powerful warbows might have a good chance of penetrating armor such as mail at closer ranges, but not any old bow fired by any archer as it seems to be in Bannerlord.
The Agincourt scenario was volley after volley after volley of arrows hitting weakspots on vulnerable enemies. It isnt an end all to the archer debate. Especially in the face of many medieval passages of armored soldiers allegedly bouncing dozens arrows left and right.
If you want to get fancy, introduce weakspot zones on characters. Neck, joints, etc. - That is where the damage should be.
Armor being decent is important. It draws more of a divide between trash and elite, it rewards the players hard work to obtain ungodly amounts of gold, and it rewards the player upgrading all of these troops to elite standard. There is also that iconic factor. When you see a tier 5 unit, it is much more interesting to view them as a real threat instead of just another arrow fodder.