While it's true that FF14 Viera are rather different than FF12 Viera—and this is one of those cases—that's certainly no reason to discard the idea entirely. Even if it's not a trait all or even most Viera have in common, there's nothing stopping someone from saying their Viera OC is particularly sensitive to high concentrations of aether.

Relatedly, Fran does refer to the aether-rich air of the Orbonne Monastery as "Mist" before correcting herself. Which is a nice nod to the usage of Mist as the source of magicks in FF12.