The thing that makes her dying interesting as a plot twist is that it would upset everyone on all fronts. Luffy would be livid at big mom for creating such a situation, big mom will blame her death onto Luffy and Nami, And Sanji would just be an emotional mess. Germa 66 would be frustrated. It adds a new twist to the prince and princess motif for sure.
Hope Oda isn't gonna go soft on us. We need some Arlong Park level drama and darkness