Have a look at the AD&D PLayers Handbook, Pg 90. It's Weapon Type vs. Arour modifiers - optional rule. We used to use this years ago to have a bit more sensibility to the combat.
The way I read is that Piercing weapons get a penalty of 3 when attacking Full PLate adversaries, as opposed to a bonus of 2 for Leather Armour. Slowed down play a bit was more realistic. Exactly like bludgeoning weapons against skeletons etc which I believe is still used in 3.5?
Also of interest is weapon speed. Makes sense that a dagger would strike before a greatsword - another sensible rule from the old school stuff.
