If I think about her removal too much I cry
but yeah, luckily she's a tough one and I can't imagine her going anytime soon, especially not with Sub Species and Sub Terra still around - they need Nemmy there to be a foundation for their themes! I imagine she'll see at least a few more revamps before she goes due to how popular she is.
EDIT: In fact, it wouldn't just be the 'Sub' attractions which need her. If she were to go, that would mean the entirety of FV would need a retheme, unless SW8 offers something similar enough to not require that to happen, but it seems doubtful that they'd use almost identical themes twice on 2 major coasters.