Or how about the system is antiquated and over-hyped?
What makes any system better, or any coach smarter? Answer: Better players!
If you have good players, any system will work. Which is my contention with Wrecks, he has never been any smarter than his players, but what he had in Baltimore, and for a few years in NY, were some great players.
His system--and his lack of coaching dexterity and acumen--is exposed when he doesn't have superstars like Ray Lewis to run out on the field.