The description says "Increases the effectiveness of light/heavy armor worn." Does that mean if the armor has an enchantment that deals dmg back to the attacker it can do more, or if it has magic resistance it'll add more magic resistance? Or does it just add straight up amount to your weapon resistances while wearing such armor?
Didn’t Ranic just ask this?
Well, from what I know it actually reduces the amount of damage you take while wearing heavy/light armor while not what is dealt back. Adding points to the skill shouldn’t change the magic resistance or the enchantment on a piece of armor. Obviously you have to wearing the specified type of armor for any of this to come into play.
It should only change the amount of damage you receive from a specified weapon not any other thing you listed above.