A couple things I heard last week:
Arians talked about arm strength. He noted that the big armed guys often haven't learned to throw with anticipation. They wait until a guy is open and then fit it in there. He said those turn into ints in the NFL.
(Btw: I think people assume that since Arians likes the deep passing game, he must love big armed guys. Listening to the coaches breakfast audio -- it seems he values accuracy, physical stature and leadership way more than simply having a gun. fwiw)
Bill Polian talked about arm strength: he noted that velocity often improves in the NFL as bodies mature, NFL weight and conditioning training takes hold, and mechanics get tweaked. He said Peyton Manning was very average arm strength wise coming out, but after two years was well above average.