That would be odd considering this scheme is meant to favor the D-line heavily. I think it is more that they are in desperate need of more help from the LB'ers and Secondary.
It's meant to favor the D-line, but it's not. There's almost no pressure on the opposing quarterback. When we played Philly, I saw Fewell only rush three a few times. Three. Now you can argue and say whether it's Fewell's schemes, or if he's afraid to blitz because of the poor secondary.