I haven't read all the responses, but I just want to point out one thing. It's not just Polamalu's play on the field that's missed, it's his leadership. He and Farrior call all the adjustments, lineups, shifts, blitzes, etc for the D. Watch the play of some of the "DB's" ,and I use that term loosely, without Troy in there and you will see many of them are out of position and looking lost.
I'll give you a prime example. On the Murphy long bomb, Ike Taylor was playing outside position and Tyrone Carter was well out of position and nowhere to be seen to cover the inside. Does this happen with Troy out there? I don't believe so. Now this could be Ike's fault, but I believe it's on Carter. I will give Taylor the veteran the benefit of the doubt on that one.
It's not a coincidence that the Steelers have lost 6 out of 7 games with Troy out. Combine that with redzone blunders and the "play" of Gay and you have a nightmare like Sunday.
Apparently Tomlin's unleashing of Hell is complete with ruffled pillows and fluffy pink bunny slippers.