"No doubt the island tried to turn eko into a locke type character, knew that couldn't happen, and wiped him out... is that what you are getting at?"

Yes, Eko was very strong about his faith...it was not based on what others tried to make him believe. Eko had an inner strength that made him dangerous. Locke is very easily swayed. His faith is only momentary, and based on his current emotions and surroundings. Lockes tendencies make him easy to control, while Eko's made it nearly impossible.