Re: Sky still falling?
No, this Defense is still reasonably good, it's just not a Super Do-All Defense anymore. The 2008 and 2010 Defenses not only stopped offenses, but they scored and turned the ball over. This Defense can just stop people now. It'll do it's fundamental job, but it's not going to win games. The Steelers can't sit back and ride on the back of the Defense to wins anymore.
The last time the Steelers went into a season with Mediocre Offense and the Defense couldn't save their skin (2009) they finished 9-7 and missed the playoffs.