While it's often measured, I'm not sure that MPH from the OF is that important?
If so,it's way behind the other factors:
-Hitting
-Foot speed
-ability to take a good route to the ball and actually catch it!
-accuracy
-ability to get the ball out quickly and headed towards the right base
My Son is an OF in a D1 program and throws 90+ from the OF, but how many times does he really need that?
An OF assist is a rarity. It's more about keeping the hitter off of second on a single and it doesn't necessarily take a cannon to do that.
To be honest, I am surprised at the number of College OF's that are really not very good defensively.
Many are former IF's or converted Catchers or Pitchers who can hit.