This whole discussion is moot to begin with, and stems from the stubborn refusal among some players to accept the necessity of gameplay/story segregation.
I challenge such players to set up "iron-man" rules for themselves, similar to the difficulty mode for Diablo III, ie, permanent death for your character the moment he or she sustains a fatal blow.
No ifs, no buts. I don't care how many thousands of hours of playtime you've invested in the character: Death is death; if you get killed, there's no coming back.
If that's fun, then more power to you.
For all the rest of us ordinary mortals, it would just be a disastrous waste of real-life hours I will never get back. And I most certainly would not want to start over from the Whispering Sands again.
And that's the simple reason why our character has plot armour, and doesn't "die" as far as the story is concerned. It's not his or her time yet.
But, at the same time, it SHOULD NOT be misunderstood as proof of our characters' immortality or indestructibility. The Warrior of Light can die, but it will take something enormously dramatic for that to happen in the story.