I'm guessing that the Ron Brace pick also gives Bill more flexibility to run a 4-3 when he wants to. In recent years the Pats have used it, but nothing much more than a mild flirtation. With Brace and Wilfork in the middle like a Vikings defense, Bill could go 4-3 for a play, a series, or a half. While I'm not suggesting that the Pats are going to go away from the 3-4 as their bread and butter defense, I think that this pick gives them more ability to do that when Bill wants to.
It also gives them a GREAT Elephant package for the goalline.