I've been thinking about something, it'd be very cool to see it implemented, but it involves changing the game's mechanics.
Currently, there is a Shield skill, that can have up to 10 points invested in it, each of which would reduce the damage done to a shield by 8%.
What I'm thinking about is turning this skill into an attribute, that would upgrade constantly with use (like the weapon proficiencies).
It seems more natural to improve one's ability of using the shield through constant use.
What do you think?