FTID beat me to it, but JJ Cooper does a fabulous job of breaking down all 53 sacks from the 2007 season. (Only 47 perpetrated on Big Ben!) If nothing else, it'll force us to not reflexively point to Sean Mahan as the sole culprit.
I wrote on SCI that Mahan doesn't deserve all the blame -- or most of it, even -- and that just an average showing by this year's center and the two guys on either side of him should go a long way in avoiding a "Big Ben=bus meat" situation. I've been wrong before, of course.
Yes, it's easy to wave your hand (waves hand) and wish Mahan to the Ravens or some such, but the Steelers signed him to be a swing player (and supposedly a backup, although I could be misremembering), and that's exactly what he seems to be. Cutting him doesn't do anything but raise more concerns about depth along the o-line and add some dead money to the cap.
And at this point, as scary as it sounds, there's no guarantee Bentley's better than Mahan. I'm coming off much more conservative about this than I really think I am; if Pittsburgh signed Bentley, I'd be fine with it, but I would have no delusions that he'd be the starter come September.
As far as Lo Neal goes, he's a bad ass, for sure, but he's also 100 and coming off an injury (right?). Is he that much better than Kreider? I know he's better than Danny, but so much so that he's worth bringing in, coaching him up, and letting him split time with FB/HB hybrid Cary Davis? Again, I'm not so sure. And again, I wouldn't be upset if the front office made it happen.
I just don't want to be one of those knee-jerk "Let's sign him!" fans that sounds the alarm as soon as anybody gets released.