Could a character ready an action to "strike the next thing that comes at him" and use it to sunder arrows or shurikens out of the air?
As long as he has the Deflect Arrows feat, yes.
Hmm, I don't see why not really. I'd allow it.
Deflect arrows is a non-action. I think this would be GM call. Unless he focusing on the archers and defending himself from them, ie not in melee, I'd say sure but give him a negative based on the speed of the arrow.
Still though, it's a bit of a stretch. Very Wuxia.
