This report, and the way Maroney has been used this year, make me wonder whether Belichick was involved in drafting Maroney. Maybe he was overruled by the GM or some other coaches. I say that because Maroney was never a "pound it inside all game" runner in college. That was Barber's role at Minnesota. Maroney was the quick, nimble guy you had to get outside to be effective. Heck, he was known as Lightning to Barber's Thunder while with the Gophers. So I don't get why Belichick would think that he can be the pound it up the middle, Sammy Morris/Heath Evans type of back. That's not how he runs. I'm not sure I would put a lot of the blame on Maroney, although maybe he has dogged it some. I think that his skill set is a bad fit for the NE offense and either he was drafted by someone who didn't realize that or they have changed what skills they look for in a RB since they drafted him.
Edit to add that, IMHO, McFadden isn't that type of back either, although he is certainly bigger and better than Maroney. He needs some space just like Maroney and wouldn't fit that Sammy Morris profile at all because he doesn't really push the pile that much.