Get serious and spend some money AND picks.
Here's a few moves I would make.
Resign Whitner- He's 4th in the league in combined tackles and is having his best season to date. Maybe a move to the 3-4 helped him become much more like what we all had hoped.
Re-sign Poz- Yes he gets injuries, but he is tied with Patrick Willis for 8th most combined tackle sin the league. He is not the problem on our D, he's an asset.
Sign David Harris- Sure NYJ would like to keep him, but they have spent a ton of money so far and may have trouble keeping him. Spend some money and add a talent like Harris next to Poz.
Sign Tamba Hali- He's finally made the conversion to OLB in the 3-4 and has had 7 or more sacks in 4 out of his 5 years in the league, he's young, and he will get better.
Sign Merriman- Many hate the move, but I like it. Even if he ends up being nothing more than a situational rusher and backup, I'm fine because I don't think he will command big money by any means at this point.
In the draft:
I would add another mid-round ILB who can shed blocks and make tackles. Derrell Smith from Syracuse is a guy I like a lot.
I would add another pass rushing OLB to push Maybin who may be on his way out. A guy like Vonn Miller, or Jeremy Beal in round 2 may be a fit.
And, I would add another 3-4 DE as a complement on the front 3. Someone who can push Stroud to the bench and add better fire against the run and pass. Bowers, or Dareus may fit that case in round 1, maybe Jurell Casey Or JJ Watt in round 2 or 3.
If we use free agency and the draft, we don't need to spend the whole draft on defense to get significantly better.