It always amazes me how crude statistical analysis is for football, especially compared to baseball. Outside of QB rating, there is no attempt to come up with holistic stat that assesses individual players or team performance. There is no equivalent to slugging pct, OPS, OBP, etc.
That said, while there is no single stat that can come close to accurately assessing a defense, total yards has got to be about the worst of the bunch. Points per game, though still seriously flawed, is a better measure (the Jets are 19th). Turnover ratio (while not solely a defensive stat) is another better choice for reflecting overall team performance (the Jets are 22).