These weren't Splashy, Front page, Day 1 free agent pickups and they were likely to elicit a "Who?" response from most fans. But Reggie McKenzie was busy working on building the core, foundation members of the team, starting with the least heralded and lower priced positions: Linebacker and non-pass rushing DL.
I'm sure the pickups have been analyzed and discuseed to death by now so I'll just add a few minor quick notes on each from a cursory initial review :
Nick Roach, LB, Chi, 6'1", 234, age 27
Slightly undersized, run-and-hit guy. Good tackler, good chase. Can be overwhelmed at point of attack. Excellent coverage. Excellent Zone drops. High effort.
Kevin Burnett, LB, Mia, 6'3", 240, age 30
Good size. Tracks and pursues the run game well. Can be blocked by Guards at the 2nd level and has hard time shedding. Good tackler. Very good coverage skills, very good zone drops. High effort.
Kaluka Maiava, LB, Cle, 6'0, 229, age 26
Undersized and slow. Disciplined. Not a point of attack guy. Will take on lead blockers and can submarine them, but will not beat them. On-and-off tackler. Very good coverage, excellent zone drops. Classified as 2-down LB, but pass defense seems better part of his game compare to run d. High effort.
Pat Sims, DT, Cin, 6'2", 335, age 27
Injury history but still young. Thick, anchor DT. More athletic than you might initially think, but still not a chase-guy. Loses his feet and goes to the ground a little bit too much. Mostly run-down DT. Looks BIG, even next to DT Geno Atkins.
Vance Walker, DT, Atl, 6'1", 305 lbs, age 25
3rd DT in Atl rotation behind Babineaux and Peria Jerry, but moved into starting lineup for several games due to injuries; was used extensively even as a rotational player. Performance increased as the year went on. Demands double-teams unless being blocked by OG like Ben Grubbs (NO). Played up-and-down the line in the Mike Nolan's amorphous defense. Can play on pass down. High effort.
Jason Hunter, DE, Den, 6'4", 271, age 29
Lined up at DE on 3 and 4 man lines. Played 2 gap responsibilities well. Is not an explosive pass rush guy nor is he a chase guy. Sets the edge, holds the point, engages the line. High effort.
The DL guys are not play makers, they are play ENABLERS. Their common attribute is that they are hard working trench guys who are there to engage as many offensive players as possible to free up the 2nd level players to make the plays. This is in stark contrast to the 2012 DTs of Desmond Bryant and Tommy Kelly, who were mostly playmaking DTs; they wanted to 1-gap slant, disrupt, and make the play, but were less effective as enablers. A side effect of this is that Sims, Walker, and Hunter had very few (if any) offsides penalties in the previous year.
This is key because the 2nd level players are not strong at playing against blockers; they are run-and-hit/chase guys that excel at running to the ball. Obviously ALL LBs play better if running free, but these LBs have more than average difficulties when engaged with blockers.
These new LBs all show great coverage skills and their zone drops really stuck out. There are two types of zone drops : one where the defender drops back to a position on the field and effectively acts as a static obstacle; the other is where the defender drops to a space and then matches up (playing man) against receivers in/around his zone. Burris and Wheeler were both the former type of zone droppers (and while I loved Wheeler, I always felt his zone drops were just a bit stiff). These three pickups are the latter type of zone defenders and show good proficiency. This should help reduce the burden on the cornerbacks in the passing game. It's almost like having 3 extra safeties on the field. Note that Roach and Burnett also showed noticeable man coverage skills as well, when assigned to the RB or TE.
The Raiders still need the splash play makers on defense, but McKenzie wasn't going to find one in free agency (at the Raiders' price). What he has been doing is acquiriing the dirty work players who will put the time and effort in to battle in the trenches so that the Glamour Defender (whoever that will be) can make the big plays.
This also puts experienced, high effort players in front of developing project players Bilukidi and Crawford. This is part of the overhaul of the Raiders' attitude and it is clear that there is a premium on team-centric, high effort, high motor players.