It would be interesting, and I could grow to like something along those lines.
But, in terms of the other obscure things, such as ressurection, there's at least built-in groundwork for that. The books seem to make it pretty clear that the past can be seen but not changed, and there isnt any wiggle room. Everything else, death especially, is left a bit more open and with purposely blurry lines.
I guess I would just be disappointed if GRRM sprung for "time traveller changes things" as part of the endgame. "Time traveller watches past but heart-achingly can't change it" is much more GRRM's speed.
BUT I'm also realizing that I'm starting to feel like a book-snob about books that haven't been written yet. So I'll just keep rambling about my anti-past-alterations.