Thats a cool theory, although it has some holes in it. Like Jack being a spinal surgeon and being able to save Ben was kind of like the Island helping Ben :/
Actually, something struck me about this yesterday. You have a great point there.
What if the island didn't need Jack, but his father? What if jack was just a tool to
bring him here? That might explain why Linus had the chance to get better and
why Jack got ill.
What if some people, like Jack, were just a miscalculation?