If people are very vocal about it, I guess they could sell some sort of job glamour for skills. Like an entire set. The job doesn't change one bit but the animation do.

However I dunno how much it would cost considering they charge 5€ for a dress. 20€ I guess?

Anyway, it could go this way
DRK - holy theme
PLD - Magitech theme
WAR - no clue

WHM - no clue... Darkness?
SCH - Magitech too (robot fairy!!!)
AST - No more star... Clockwork!

BRD - elemental archer?
MCH - less flashy, some people complained

SMN - no clue except demibaha - > demi Alexander
RDM - replace some elements by others.
BLM - "ice mage" sounds too simple, I guess some sort of void magic, like some sort of dark fire etc.

I mean, while I don't think something like this would ever happen.

To me it seems more likely than them adding a holy dark knight as a new job. (I mean, there's still Templar but I don't forsee any new tank for 6.0, so 7.0 would be a looonng wait) and I don't think they'd go for a theme one of the tank already has (holy). If anything they'd save the spot for a dps as no dps has the holy themed attached to it.