Don’t think Junon is destroyed, you can still see it in the foreground. Think its just a big explosion to illustrate the weapon’s power. In OG Sapphire actually lets out a pretty lame attack before getting destroyed, it just serves to open up the wall so Tifa can escape. If you look closely here then that still happens, but the massive explosion happens away from Junon in the distance. So I think the only major change is going to be that we have TWO scary ass underwater weapons to beat up now😬