Not that it wouldn't have been great to get Mack, but (historically speaking) Pettine's defenses have centered around very strong DL play and ILB's, with less importance (compared to the magnitude of Dom Capers defenses) placed on the play of OLB's.
Pettine took the reins as DC for the NYJ's in 2009, and his defense ranked #1 in fewest yards allowed/game (252.3) and #1 in scoring defense (14.8). He did that with Calvin Pace and Bart Scott at OLB. David Harris was the key MLB who did a lot of damage with 5.5 sacks and 2 INT's.
In 2010, with the same guys at OLB his defense was ranked #3 in yards allowed and #6 in scoring defense. MLB David Harris, again was strong in the middle with 3 sacks and a recovered fumble.
In 2011, Mo Wilkerson gets drafted. Defense ranks #5 in yards and 20th in scoring. MLB Harris has 5 sacks and 4 INT's.
2012 his defense was #8 and #20 and 2013 (as DC for BUF) his defense was #10 and #20.
Pettine's defenses (based on his track record) tend to do most of their damage up the middle with the DL and the ILB's. His use of OLB's seems to have been more for run containment and sacks gotten from the pressure up the middle forcing QB's off their dime.
If GB's DL can play as well as is hoped, and Martinez can have the kind of year he is hoping to have, it somewhat calms that "If Only" nerve about not getting Khalil Mack.
The draft next year is very strong/deep at DL, but also has a good group at Edge/OLB. If Gute plays it right, they should get a couple solid guys with those two picks. IIRC, Matthews was picked at #26. Here's hoping!
Here's a couple of Pettine quotes from earlier this year.
“It starts up front. If you want to defend the pass in the NFL, people talk about the exterior pass rush, I think the interior pass rush is as important or maybe potentially more important.”
“If I’m on offense, it’s a lot easier to handle guys off the edges via formation, or chipping or doubles. Whereas inside, one guy, maybe two they’re getting one-on-ones. Those guys have to win. If you can be dominant inside, that just has a ripple effect throughout your defense.”