So Locke's got back issues before the island, and if 815 never crashes then presumably he still is paralyzed. So say there IS a reset. Something tells me our favorite back surgeon, Dr. Jack Shepherd, will end up meeting Locke via this.
Locke will seek a miracle doctor to help him out.
Jack will say something like, "You'll never get better."
Locke replies, "Dont tell me what I cant do."
Jack WONT do the surgery, last time he tried that guy ended up dead.
Locke will get depressed and hang himself.
Jack will feel guilty about Locke's death...once again.
I dont know why yet, but he will get on Ajira 316 and everyone else will, including John Locke's corpse.
Reset - but whatever happened...still happens.