+1
I think that a shield or parrying dagger should have properties that allow you to increase you MDD to d8 when parrying, and sheilds should make it VS any attack (yes even fireball)
The more I think about it, the more I believe there should be two sorts of manoeuvres. Some which you can do no matter how you're equipped. Crazy flipping around to avoid a fireball, say, like a monk or rogue might manage; managing to make even blows that your opponent blocks do some damage, like a fighter. And some which are associated with equipment. You have a shield, you can parry melee or missile attacks; you're a monk with weird martial arts weapon or a rogue with a parrying dagger, you can try to disarm enemies with your MDD.