I think you're probably just going the devils advocate route because that is what you said you are doing a few posts up but even then this is a tough list.
Bell has missed 1/2 the games for the Steelers the last 2 years and their offense has still been good when he has been out.
The Ravens were down 23-3 and pretty much getting dominated until NE had 2 special teams fumbles that set the Ravens up for 2 easy scores.
And Buffalo 16-0, I'm not sure what your point is? 16 is less than mid-20's.
The bottom line here is that the playoffs are a whole different season.During the regular season it comes down to special situations like consecutive road games,playing a opponent next that you are thinking of more than the one your playing(buffalo),and just so happens buffalo always gives New England a tough time in at least one game during the season,so the factors that play in during the regular season you can throw out the window cause they don't matter now.Also in the playoffs, teams like New England always get a 2 week window, and that is a lot of time to prepare for somebody,especially heading to the super bowl....so i agree with you on what you said, as you prepare differently for your next opponent and in this situation i don't think Atlanta has a top notch running back,and even with Bell going out of the game, i still would say Williams is much better than either of the Atlanta backs