I think the concern is from the more traditional football thinkers. I am a quasi-traditional football guy. And that is not a pretentious thing, it is just a matter of opinion and preference.
There is no denying that the Cardinals are creating a pass rush through what JoeSchmo wrote up above.
But we play a 3-4 and traditioinally the majority of your pressure should come from the OLB. We are lucky to have the front three of Dockett, Campbell, and Alan Branch. Yet, the pass rush abilities of our OLB'er leaves a lot to be desired. While I can easily look Okeafor and Haggans in the eye, and say "good job", there is no denying both are old and slow. Solid players, especially for their age, but old and slow.
When you think about OLB'ers in a 3-4, you think of Carl Banks & Lawerence Taylor, Pat Swilling & Reggie Jackson, and Gregg Lloyd & Kevin Greene.
And that is optimal. At this point, and many teams do this as well, we will take anything we can get. Just one out of the two OLB'er positions.
Guys like DeMarcus Ware, Elvis Dumervil, Terrell Suggs (ugh) or James Harrison would do fine even without someone at the other OLB'er position.
The problem ? These types of players are rare, and you gotta watch you don't pay 22 million to a guy that is only going to produce at most 7 sacks, ala Calvin Pace. You can get a guy to get 7 sacks at a quarter of the price, IMO.
You gotta draft a good OLB'er and then cross your fingers that that guy is not a bust, which if you look at the past drafts it is an extremely high risk situation when drafting a pass rusher.
So, it is a concern in a traditional sense, but the Cardinals are making due with what they have, which is a sign of a good football team.