Armour mechanics in BB is very simple and clear, if devs want more realistic mechanics they should remodel whole weapon damage mechanics.
Weapons should have new parameters like:
1) weight: more weight and more impact force after hit = more bludgeoning trauma after hit and higher bonus to armour/shield damage and more fatigue
2) point of balance: if point of balance is closer to the hilt then accuracy and defense is better and fatigue is less but impact force is lower and less bonus to armour/shield damage
2) type of damage:
2a) slashing: high chance for bleeding, low damage to armour
2b) piercing: high chance for critical damage, very low damage to armour
2c) bludgeoning: high chance for stunning, low damage to chainmail and padded leather, high damage to plate armour
2d) hacking: mid chance for bleeding and stunning, medium damage to armour
4) special structure: for example curved blade is better for slashing and worse for thrusting
After rebuilding weapons parameters now we can change armour mechanics. First of all armour should protect percentage portion of damage.
1) Chainmail provides very good protection against slashing, good protection against piercing, medium protection against hacking and almost no protection against bludgeoning (but most of chainmail users wears under chainmaille padded gambeson). Chainmail is heavy and has bad point of balance (all weight is on your shoulders) it should give a lot of fatigue.
2) Padded leather provides good protection against bludgeoning, medium protection against piercing and hacking, and low protection against slashing, it’s light but heats your body so fatigued is not so low as (but still lower than chainmail)
3) Scale armour provides good protection against slashing and bludgeoning and hacking, medium protection against piercing. It’s heavy and limits movement (lower defense)
4) Plate armour provides very good protection against slashing, good protection against piercing and hacking, medium protection against bludgeoning. It’s heavy but the wieght is evenly distributed so fatigue is less than chainmail, but it’s limits movement alot.
Now we can assume how many percentage portion o damage is very good (99%), good (75%), medium (50%), low (25%). After hit mechanics check what was the type of damage and how many damage target has received, and it compares those parameters with armour type. It calculate how many damage passed through armour and how many damage damaged armour. It’s more realistic but it requires a lot of work to find proper balance.
Honestly speaking, I did exactly this for a game called battle for westnoth, it took me a week to change all the values and balance for each and every unit of every single faction but it was so worth it :D