"excellent" coverage would not allow the catch. Again, great CBs do not allow these "amazing catches on excellent coverage" to happen. They locate the ball, they challenge the WR and make the WR obsolete.
This style of CB play doesn't even make sense for Marinelli's defense. We are a bend but don't break D, this defense is supposed to be creating turnovers and it's how Marinelli actually made his name in the NFL.
Not getting turnovers is why Stafford could march down the field with ease. We have never had the right style of CBs for Marinelli's defense and he's partly to blame.