I was at the Pats 20-3 Colts win at Gillette a couple years ago, it was a freak occurrence that I got tix from a friend, haven't been there since. Maybe that's not enough of a sampling, but it was a playoff game. Bottom line is, sure, it was loud, but I've also been to college football games. Those are loud. You can't deny that you need some serious $$ to go to these games - which proudces a different kind of crowd. It's not exclusive to Pats games by any means - Sox are getting commercialized, the C's (or B's) actually have the highest percentage of real fans in the stands to be honest. IMO, at least. (EDIT: It's happening elsewhere too, but I've noticed other NFL stadiums seem much louder than Gillette).
Your point about the making a difference on the field (due to acoustics) is a point well taken, but even Pats players themselves have complained the past couple years about our fans. So, take your beef up with them first, and I doubt they'll care about acoustics.