Instead of reducing damage or making you harder to hit, what if armour had its own HP?
Any non-critical hits would first be taken from the armour's HP. Crits do two dice of damage - one to armour, one to the character's HP. I've been thinking recently about having two kinds of crits - one for 20's on d20, and one for 6's on damage dice, so this would be for rolling max damage. More on this in a later post...
Just like a character, the armour would be able to be "healed" - but in the case of armour, it would require time and tools.
This would give an advantage to the lighter armours - as the armour gets heavier, so does the repair kit! At the high end, you're not going to be making much in the way of repairs to your plate without a set of hammers and an anvil - hardly typical adventuring gear!
Thinking out loud here, but let's toss some numbers together:
Armour as HP
Armour
|
Armour HP
|
Repair time (max HP without proper tools)
|
Tools Required
|
Max HP with lighter tools
|
Cloth
|
12
|
3 hours
|
Scissor, needles, thimble, strong thread
|
3
|
Leather
|
12
|
3 hours
|
Sharp knife, scissors, heavy needles, awl, thimble, strong thread
|
3
|
Chain
|
18
|
24 hours
|
As Cloth, plus:
Wire, wooden core, wire cutters, pliers
(Optional - mechanical wire winder, specialised pliers and snips, premade rings and rivets)
|
14
|
Plate and Chain
|
36
|
48 hours
|
All of the above, plus:
Several hammers, heavy snips, steel plate, files, anvil
(Optional: spare plates, straps, buckles, etc., planishing stakes, dishing stump)
|
27
|
Repairs
Without proper tools, you can't repair the armour.
If you have the proper tools for a lighter armour (i.e. have Cloth tools but Chain armour), you can repair the armour to the level shown in the last column.
If you have the optional tools, knock 25% off the time.
All of these times are for field repairs - expedient, but probably not pretty.
Unbalanced Weapons
Unbalanced weapons would always do 1 point to the character's HP, even on non-critical hits.
Credit
I thought of this after re-reading this post on Untimately:
http://untimately.blogspot.com/2012/06/evasion-armor.html