I fell asleep, and missed all the excitement. This is great news. McCourty is a special player and the way the league viewed him should point out how valuable he is. He has unique (for now) skills as he could be a stand out CB. That allows Patricia to do more with him than just play a single high S, or 2 deep.
Obviously his range and anticipation go a long way to allowing all of our CB's to be more aggressive when they are playing man or zone. But even more than his physical skills you can't underestimate the value of his leadership and durability.
On the surface it looks like the Pats might have had to overpay a bit more than they would have liked. I would guess $8-8.5MM/yr would have been their preferred range, but his leadership would have been hard to replace (especially with Vince gone)l, PLUS his durability made it easier to make the move.
When the details on the deal come out, look to the guaranteed money. That's the important number, not the total value of the contract.