I would consider getting rid of the distinction at the skill level between heavy and light armor.
The principles of light and heavy armor are similar. Both come in parts, fit together and face similar issues as far as wearing an putting on, and suffer similar damage from combat.
Benefits like reduced armor and noise should be pooled together into one skill. Just plain armor. I would also add a benefit to that is that the apparent weight of equipped armor is reduced.
To those who don't know how to properly put on armor, it might feel 20% heavier, and to the very skilled 20% lighter than pack weight as they have learned tricks to better balance and secure the armor.
Then each type of armor (leather, studded, chain, half-plate, plate, full plate) would have a noise rating inherent in the armor, like durability is inherent in the material type.
And then there could be two (or perhaps more) different style skill for how you want to use the armor you have. Like there different attack modes.
One style might be the fortress style. You learn how to use strong points in the armor and the materials durability to absorb damage. This would let you pull more of the armor rating out of the armor then the base AR, as well as damage reduction by letting the armor take a portion of damage.
(1- ( (X ) * (Y) * (Z) ) ) * Dm =Di
( (1000 ) (3) 2100) ) )
Where X is a random number from 1 to 40,
Y Skill in Fotress style defense.
And Z is average durability of equipped armor. (Probably weighted % of body that any piece is covering)
Dm is damage roll of the monster, and Di is the recieved damage
Or what was in my head 0-4% reduction for every three levels of skill while wearing the best armor in game.
The constant on the bottom would probably need to be balanced.
Further balance could come from adding bonuses for endurance, strength and concentration.
The other style is what I would call the monkey style. Involves angling and stepping to avoid attacks or using protected body parts to deflect incoming attacks.
Increase in skill would add some aspect of dodge (as many people don't use it on it's own) and increase armor rating. The dodge aspect would suffer moderate penalty for a lot of weight and the AR a slight penalty. Additional bonuses derived from dexterity, concentration and speed.
Bonuses are proportional to the weight and skill
AR bonus = 2X - 1/10 Y + 1/5 Speed + 1/10 DEX
Dodge Bonus = 3X/2 - 1/5Y + 1/5 Speed + 1/10 DEX
or (2x-10) - 1/5y + 1/5 Speed + 1/10 DEX
Where X is monkey style skill, and Y is appearant weight of equipped armor.
The default if just armor is known could be old style, were you get small bonuses for all the physical stats, and AR and DR in proportion to the old bonus system using a hidden light/heavy armor categorization.
Of course it would all have to be balanced but this is just a rough stretch. I think it could introduce real differences between armors and open up more distinct methods of game play.
If you dropped dodge on its own and modified the shield skill to compliment each of the different styles in it's own way in addition to the standard missile blocking, you would see 10 possible unique development strategies from combinations of 4 defensive skills. And there would be fewer walls apparent to the player. Penalties, yes, if you try to absorb damage with hemp it will only work 10% as well as divine ore, and if you want to dodge something wearing full plate... well good luck.
Old style, old style with shield, Monkey, Monkey with shield, and Fortress with Sheild. and probably less used fortress without shield. Also would be the choice for non old-style styles would be weather to improve the technical aspect of armor. (noise, durability, fit/ appear antweight)