The fake punt was not a bad call, and I fully understand Tomlin's thinking here. Punt, and New Orleans drives the length of the field in four minutes and the game is over. That defense is not stopping Brees with four downs on every series, and all three timeouts remaining, no matter where the Saints start their drive.
On a fake, you've got two decent possible outcomes:
1) You get the first down, near midfield or better, if it really pops. Then you're in complete control of the game.
2) You get stopped, but give New Orleans a shorter field -- seems bad, but if/when they score quickly, Ben should have enough time left for a final drive to tie or win.
The latter actually happened, and if not for JuJu's fumble, might have worked to perfection.
HOWEVER, once again Tomlin made a gigantic challenge blunder by not throwing the red flag after the Thomas catch/fumble early in the 2nd quarter, with the score 7-6. Thomas catches the ball cleanly, establishes clear possession, and takes a full stride and a second step before Davis separates him from the ball. Why not challenge there? WHY? He had all the time in the world to do so after a "no foul" sequence from the referees.
I cannot fathom why you would not want to at least have them take a look at a game-changing play such as this. Had the play been overturned, the Steelers would not have gotten the ball at the 30, but still would have had it at the 15, where they had a clean recovery.
The only explanation I can come up with was that Tomlin was living in his fears after losing 10 straight challenges. Bottom line is he really ****** his team.