I've seen things about it, it's a really cool idea but at this point I feel like Star Fox really needs a new game (that does well) featuring Krystal to really help her chances of ever being playable in Smash.
I think Krystal fans specifically all around the internet should band together to create a vocal and enthusiastic community promoting Krystal's relevance and appeal to Nintendo (and on-lookers). Similar to what K Rool fans were doing a little while ago! Krystal still has so many fans it's crazy, the problem is that they aren't vocal enough about it to Nintendo. If all of Krystal's fans continued to post about her, draw fan-art, etc and Nintendo was able to see that (by @ing them) then I really feel like Krystal's return will be inevitable.
I saw the Krystal artbook that was organized and sent to Nintendo a while ago, THAT was a really great idea. If we can grow that vocal community and continue expressing our support for Krystal online as well as directly to Nintendo - I feel like that is the most effective direction going forward personally!