I'm guessing a chunk of his success comes not from him, but from who else is around him on the field: i.e., Diggs.
Diggs is going to make everyone around him look better as the defense is looking to defend him first and foremost.
I also think Davis has sort of deceptive speed--like he isn't ultra fast in an artificially timed track meet type of setting, but with all that gear on in a real game setting, he's faster relative to others on the field.
And he always looks BIG and STRONG to me, with a naturally powerful build. Not sure that helps him on these deep balls, but it helps in some situations when he can go up and just take the ball out of the air, even while defended.
I would be trying to turn that guy into an absolute superstar with Josh's arm!