Maybe the item that Lois is wearing in the last scene of BvS has more than just sentimental value and it is key to Superman's future timeline.
I feel that Superman's resurrection in whatever future film will be a surprise. Snyder has hinted at such that Superman once resurrected, would come back "different". Some say Snyder may go with a bad Superman. I think that's a possibility. An equal possibility is that I think Snyder might deliver a more "classic" characterization of Superman once he is resurrected. As in a more positive, more righteous, less "modern" characterization. It will be interesting to see. I don't even recall that, need to re-watch the film.