When I first read this interview with retired QB Kurt Warner, via ESPN's NFC North Blog, I thought he was talking about the beating the Green Bay Packers. But instead he was talking about how to beat the Steelers. You force their linebackers to cover wide receivers down the field.
Warner said "If I had four receivers where I could force those linebackers either to cover, to get out in space, or to force them off the field, that's what I wanted to do. I wanted to take the strength of a team and attack it."
His comments reminded me of this play against the Steelers in December 2009 when the Packers managed to get WR Greg Jennings in the slot against LB Lawrence Timmons, who is a very good linebacker but can't keep up with Jennings in coverage. But there is a downside as Warner said ""It leaves some short edges for guys like James Harrison and LaMarr Woodley coming off the sides...You've got to get the ball out of your hand."
Back to my original point: at first this sounded like a discussion on how to beat the Packers. Warner and the Cardinals used bunched sets during last season's Wild Card game to force LB Nick Barnett into coverage against a wide receiver, and the results were horrible (for the Packers). And it was devastating because Warner can get the ball out of his hand so fast. Maybe that is a sign of the similarities between these two defenses: you can attack them in the same way.
I expect the Packers will use their top four wide receivers on multiple plays and packages during the Super Bowl, but they usually leave one or two blockers in the backfield for pass protection when QB Aaron Rodgers is in the shotgun. It will be something they'll use at times, but they can't go with it exclusively.