Part of that is by design, Marinelli plays a wave attack and I would argue that the combination of McClain and Thornton gave the Cowboys above average play at the 1T.
DLaw is a good player who would give you double digit sacks if he was healthy. Tyrone Crawford would have had better stats if he was healthy all year as well.
Also David Irving had flashes of dominance, I think he just needs the reps to become a very good player in the NFL - and one that has the potential to be a dominant player. He has certainly been dominant in stretches.
Also Maliek Collins should be significant better next year, most second players improve considerably with more film study and weight room work.
McClain was really good for a stretch this season but struggles with health too much to be relied upon.
Thornton has been overall a disappointment, saying himself that he has struggled with the scheme and needs to step up. He played better toward the end of the regular season but injury also ruined his possible contributions.
Not sure about DLAW, his back injury is a major concern that could linger and with a contract year coming soon, you just have not seen enough to justify the money to keep him including the significant injury risk factor.
DLAW played well with Hardy at RDE in 2015 and flashes but is also inconsistent when looking at the total body of work.
I think David has potential and flashes but is inconsistent, only time will tell what he becomes but you can not count on that as a given.
Collins shows promise and will get better definitely a core piece at 3T.
Tyrone Crawford has been injured often and simply has not produced enough to warrant that bad contract.
Gregory may never play again, time will tell.
Tapper is a complete unknown with a back condition that could be problematic for his career.
We need an influx of DE talent in the draft and someone with ability in free agency yet again, we shall see if they can get it right this time.
We need a game wrecker and some play makers on defense, truly on all levels of the defense.