The notions that SA will be destroyed simply because some of the borders might be redrawn is really a hysterical observation.
Unless I am significantly misunderstanding, that is not what is being said here.
The fear is not that SA will be destroyed, but rather that it will lose its hegemony and its power over the doings of realms—which will destroy what makes it unique and special in BattleMaster, and reduce it to being just another flavour-of-the-month also-ran religion, like nearly every other religion in the whole game.