Yea, you could well be right Dec4denc, it's very possible that Jin could be alive with Sun not in the loop (Hugo looked shifty imo).
However the creators did once say that what we see in the future is "set" - i.e. it's canon and not a dream/alternate reality etc..so i wonder whether that also applies to deaths which might not actually be deaths - I hope not because i'm thinking the man in the coffin (3.23) also has more to it than meets the eye.