I must say that i find the whole idea of this very interesting.
Althou it never came up at my table and i must admit i would not bring it there aswell, BUT if anyone of my PCs came up with this i would allow it. Just for the reason of it beeing a "cool and funny" idea.
I am aware that it might open up discussions about other stuff aswell...
But here is why and how i would handle it:
I don't think it devalues the feat Defelect Arrow:
Due to this feat allowing you to negate one arrow of your choosing for free anytime this happens - even that critical, fired from anyone of those 4 Archers over there.
And you only need to be aware that you are beeing fired upon.
which i would assume you are aslong as the archer isn't hidden / you're flatfooted.
Also readying an action effectivly renders the defendee (?) more or less "useless" for the rest of his turn.
But how to put this into numbers or make it possible?
Well, if we look at that video of the guy hitting the pellet midair with his katana we can see that he is concentrating on that one shot and he most definatly has reflexes / hand-eye coordination beyond the "ordinary" human.
So how would that translate into a martial PC doing this?
I would have him require combat reflexes, just because he is trying to react to something fast AND since he is has to focus all his attention towards the (one) firing archer i would count him as flatfooted vs others attacking him. Maybe even let enemies resolve their melee attack vs his touch ac, since he would effectivly not be moving around as this would make intercepting the arrow impossible.
After this i would just let him resolve a simple cmb / cmd unmodified to see if he manages to hit the first (and only first!) arrow at all.
This way it would make it possible for a PC to do it all the while still requiring some sort of feat all the while making it more or less impossible for the avarage commoner to perfom this.
I am aware that this could possibly lead to PCs asking if they could intercept spells this way, but that would be a straight "no!" from me.
Since there is a feat for that and i personally (!) think that spells move faster than arrows / projectiles. Also if they are going to "shield" of a fireball with their shield it wouldn't prevent harm and most probably even result in a broken or destroyed shild...
tEF