He's been great this year. But keep in mind teams had zero NFL film on him, now they will have a whole year's worth. Every player has weaknesses, OCs aren't stupid (well most of them aren't), they will find ways to reduce his effectiveness. Remember how most were praising Roy Williams his first couple of years, then teams found out he was poor at coverage, they put him in positions of having to cover tight ends, etc. and he wasn't all the rage anymore.
And the way the Cowboys used him this year, in most every defensive position, simply isn't sustainable over the long haul, he'll get worn out before long.
He has the potential to be one of the all time great Cowboys, and NFL players, but it's a long way to Canton, here's hoping he can keep it going...