Tank is still a really good team first player. The guy is a really good strong side DE. He plays extremely hard, he wants to win and you can see it in his play. He plays with a mean streak and that something not many Cowboys players possess. Sacks are great but not the only stat to go by, my suggestion would be to look at explosive plays, instead of just sacks. It’s pretty much a guarantee that he will get an explosive play (Sack, TFL, FF, PBU) per game. That’s extremely hard to find, and those plays change the outcomes of games. He’s not a sack master, not many SDE’s are but he does a ton for this defense.
The only other true SDE the team currently has on the roster would be Gholston, and he doesn’t bring a whole lot to the table, not a bad rotational guy but he doesn’t scare anyone.
I don’t think Tanks salary isn’t out of proportion to his production. As long as he continues his level of play this season I’d not only expect him to finish out his contract but would welcome it.