Sure, he made a lot of not so stellar plays this season/playoffs, but he didn't make a lot of bad decisions. A lot of times when you have a really good defense, all you need from the offense is not screw up too much.
Newton has all the physical tools in the world, but he's still got a lot of learning to do. His performance on Sunday showed that. If he does become as mentally able as he is physically able...look out every other team he faces.