Well, Atwell has such limited ability to play slot that calling him a slot player is pretty generous. Guy just doesn't have the change of direction to be used there regularly. He can only really play there on with a very limited route tree. Atwell has speed and actually pretty decent hands but not much else.
I'm pretty generous with this front office and think they've actually gotten quite a bit more right than wrong but Atwell seemed like a panic pick by McVay with a player he probably liked in Eskridge coming off the board right before him.