That bothers me about Elena's character. She's not a nag, but becomes one. That's just how I see Liz becoming if she and Will marry. I'm not convinced anyone will die or will not die. And to be fair, I've never saved my fiance's life and I feel we are worthy of each other, lol. Will tries, and that's what matters. Jack is just in the right place at the right time.
Jack does deserve her more because he seems to need her more. Will needs someone else. I think he could be "Jack" for some girl, just not Liz.