So everyone (including myself) who was scratching their head about why New England picked up Albert Haynesworth and how he'd be utilized may have just gotten their answer:
The 3-4 defense has been used throughout Belichick's tenure in New England, and is used nearly twice as much in the AFC (9 teams) versus in the NFC (5 teams), with all 4 teams in the AFC East employing it. This may create some confusion for those teams especially, having gotten used to certain looks from the playbook from certain players.
In any case, it caught my interest. Rarely do you see a coach vary from an offensive or defensive philosophy, especially when success in those philosophies has worked. More rarely do you see coaches with the tenure to make such a move. When you consider their roster (another subject entirely), you can see why this would make sense, given some of the changes in personnel over the last few years. The signing of Haynesworth is very bad for the rest of the NFL if this is true. He could be a total monster in New England back at the position he once dominated. Dan Snyder will weap audibly.
New England rather quietly just acquired a #1 receiver who could play to the end of Tom Brady's career, a backup QB who has the physical tools to dominate the league if he receives the proper coaching (and has time to sit behind Tom Brady), and one of the leagues top 3-5 defenders 2 years ago.
I hope one day we will be able to see that happen with the Lions and see it as an 'interesting development'.