He garnered A TON of respect from the Patriots. They came out and said we are glad he retired, because he sacked Tom Brady more than anyone else did.
He was definitely not over rated. He was a great player playing in one of the worst eras of team history (a plethora of years of mediocrity and crap).
I had a lot of respect for the man. I wish he would've continued playing, but 10 years on nothing but losing teams, and shouldering a defensive line that was lackluster gets old, and wears down on you fast.
I don't think he'd be able to come out of retirement, but it would be cool if he came back to the form that he was in before leaving (and this is JUST HYPOTHETICAL...)