I thought that when the Pats went into Wildcat, I saw a lot of Vince Wilfork just punching through the line and getting into the backfield, versus his normal 2-gap responsibility.
I read Cowher's NFL.com piece about how he would stop the Wildcat, and that he said you need a player in the backfield at the mesh point (Where the handoff/fake handoff happens).
I think when the Pats saw Wildcat, one of the way their defense changed was to allow VW to just get into the backfield any way he could.