I said a few weeks ago the Cardinals current personnel is better suited to operating a 4-3, than the 3-4. The greatest weakness is at OLB, the very same that needs to be a position of strength (along with the NT) to effectively operate the 3-4.
The D's number one problem is they are not getting any pressure on the QB. In the 3-4 that pressure has to come primarily from the OLB's. Berry, Okeafor, Haggans are all too long in the tooth and too slow to get it done.
If Cardinals ran the 4-3:
DT - Watson, Robinson, Branch, Iwebema
DE - Dockett, Campbell, Okeafor, Berry
MLB - Hayes
OLB - Dansby, Okeafor, Haggans
Seconday same as now.
But let's face it they aren't going to change horses in mid-stream. And it will limit this teams potential this season and likely next, because they will not pick up enough FA or draft picks that are going to change it in one year.