He's a Superhuman
Somehow, McClane became a superhuman. This was inevitable, and we see a bit of it emerging in Die Hard with a Vengeance's truck-surfing scene, but when McClane takes down a harrier jet in Live Free or Die Hard, we're about as far as we can possibly get from the barefoot everyman showcased in the original Die Hard.
A Good Day to Die Hard shows no halt or reversal of this trend. It's just the sort of thing that happens when films get to their part five. Except for Rocky. His part five gave him brain damage. That might not be such a good idea either.