I don't want the devs to give up on Chemist

[Kozh]

GNB and MCH don't use their aether to cast spells tho. Their GCD actions are categorized as "Weaponskill" instead of "Spell" even when using aether.
In order to be grouped with the other healers, Chemist need to also cast spells. Otherwise a stat like spell speed and battle mechanic like silence won't affect them and it wouldn't work.

I think you're confusing job aesthetic with gameplay. Lore wise, all jobs use aether. And the "weaponskill" and "spell" probably just due to DoW and DoM category. Like I said before, chemist preparing their potion can be seen as "casting spell". It's no different than whm standing around while casting.