I'm in the group that thinks Costa could be very good...but I do have concerns about the back. He has to prove he can stay healthy, although he never had back concerns in the past.
One thing I notice about scouts is that they look at a player and they see measureables....good feet, good hips, great leverage, etc....and they project that the player should equal the sum of the parts. What they sometimes miss is just watching the player in action. Ogletree is case in point....everyone says he runs good routes, yet when you watch him in a game, he just doesn't seem to be where he should be.
Scouts miss too...all the time. Biggest reason is you can't measure the player's heart and determination.