I know different ideas are supposed to go in different topics, but these go hand-in-hand, are not two ideas, but one.
Armor Weight
My search turned up some slightly similar ideas, but they were related to speed. The way i see it, there are two types of armor: Light and Heavy. Light armor is made of cloth and leather. It has no effect on Stamina, it's just protective clothing. Heavy Armor is made of metal. It should make your stamina drain faster, and maybe you shoudln't be able to sprint at all, although if you could, you wouldn't get very far before running out of stamina due to the weight and sweltering nature of heavy amror. After i explain the next part, i will go into more detail.
Damage Types
Didn't turn up much in this search. There are four basic damage types: Piercing, Slashing, Chopping, and Crushing. Piercing is Arrows and stabbing weapons (like daggers, hint hint) and they are fast (arrows move fast, and daggers are so light they can be used quickly), but they also not very powerful by themselves. Slashing is swords and stuff with blades designed to cut things and is average in damage and speed. Chopping is axes, and it is a little stronger than slashing, but also slower. Crushing is the slowest, but it hurts!!! We don't actually have any crushing weapons, but we need some clubs and maces.
Armor vs. Damage
This is how the above relates to each other:
Piercing Damage works agaisnt all Armor
Slashing Damage works agaisnt Light Armor, but not Heavy
Chopping works against Light and Heavy equally
Crusihing works against Heavy armor, but it's attacks are softened by Light Armor.
well, it needs a little more, but i want to see what people think about as is, and see what they think they need added or subtracted, or if it is total crap...