You obviously haven't watched Darwin walker play. He's not a turnstile. And the Eagles have had a good run defense since they lost to the Steelers. Atlanta was the top running team in the NFL and the Eagles stuffed them.
While Darwin Walker might have had an attitude problem in AZ, self-admitted, a good coach will find a way to turn that around as Andy Reid obviously did. Plus, the Eagles have had a lot of really high character guys, particularly on defense.
In some ways the Eagles and Patriots are a lot alike. Good organizations know how to recognize, work with and development talent. Bad organizations, like the Cards throw it away.
Of course in Philly we have the Phillies incredible poor organization to balance out the Eagles.