I may be crazy, but I don't think the secondary's problem is the ability to cover in general. The DBs seem to be pretty close to the receiver most of the time (any closer and their feet would get tangled up with the WR).
The problem to me, other than Sutton, is that they don't seem to have any balls skills (don't know what to do as the ball is arriving). The great DBs seem to have the ability to know when the ball is about to arrive (watching receivers eyes or body language perhaps) and they turn and are able to defend the BALL. Our DB strategy, again other than Sutton, seems to be one of deterance. In other words, cover the receiver close enough that the QB sees them as covered and doesn't throw them the ball.
If this doesn't improve, I'm afraid our DBs will be continually challenged even if they seem to be in good position until this is corrected. Maybe BG's receivers are just much better than others we'll face and I hope this is the case. If I'm a OC playing us, I'd tell my QB to go ahead and throw the ball to any receiver that is being trailed on a sideline play (where safety help is difficult) no matter how good the coverage seems to be.