You bring up some great points.
Another question I have is why ever run an empty set? Especially with a QB with a bum shoulder, to me its a whistle to the D-linemen to rush like hell. No run threat even from the QB. If you need one more guy on the route, send out the RB.
Going empty, especially with a running back in the field, reveals the coverage of the defense. That means if your man wins you should be able to get an east completion.
