He's not even near the top for big's in the league let alone player(s). A couple blocks/g don't equate to being a "good" defensive player just like JB completing a few 20+ yard passes doesn't make him a "good" passer. However, you'll make excuses for one but trash the other..
If it's on the radar, it's a "like to have", but I think CB, LB, WR, and DL are all "need to haves".
They're giving up the 4th most points in the league (28ish), and would be *s if they ignored the D early. If they think they can make some big FA move to correct things, OK, but they are a lopsided team, and the O (who is lacking really only WRs) is much farther along than the D.