What it says on the tin. I really don't like how damage is all or nothing these days, which renders some weapons totally useless (wood bow, I'm looking at you).
Instead of blocking x/x, make armour block x%/x%. Of course, this doesn't really scale well with quality, since you could theoretically get a set with over 100% protection and thus get healed by getting hit. But quality of stuff should matter, so it should be plugged into the damage formula somehow. For example, actual blocking value could be armour q / weapon q * base block value. This however gives advantage to weapons as the q rises, so perhaps weapons shouldn't get bonus damage from q.
Anyway, this could work well with potential future developments. In addition to damage, weapons could have armour piercing value, which would be a multiplier to their q for purposes of calculating how much damage gets through. So you could have military picks that have low base damage but virtually ignore armour, or sabres which have high damage but are crap against armour. Armour could, if multiple damage types are implemented (blunt/slash/pierce), have bonuses of it's own vs specific damage. So you could wear a balanced set, or put all in pierce protection (losing on other protection) if you're expecting to face archers.