I think alot of it has to do with him trying to prove something to himself, because he always saw himself as useless because of the way he was put off by his parents. I think that when he was placed in the wheel chair that something clicked in him, and he decided to no longer be the victim and learning to hunt and survive somehow broke him out of that mold. But also, I think that he does have some sort of special relationship with the island aswell that enhances his abilities and gives him the ability to be healed.
Deffinetly agreed! I think Locke will play a big part on the island as the show goes on..