Tried to design Chemist

[Shurrikhan]

Tangentially...
This puts me at two minds with regards to Scholar...

Agreed on these points. I just feel that the distance indicated here allows plentiful berth for SCH's future advancements. It's not a matter of principle -- taking opportunities, where presented, for new jobs over conserving them for old jobs' advancements -- either; after all, I still think Conjurer would fully and compellingly eclipse Geomancer, or at least provide a base job for it, provided that the devs were ever willing to separate job-experience progression past their branching points. This is simply one where I feel the difference in techniques and alleged purpose are sufficient, and differences in lore, style, mood, and aesthetic are more than sufficient, to warrant something separate from Scholar. I'm all for improving upon Scholar and finally fleshing out its identity as more than just differently flavored approaches to a generic healer kit. I just don't think it needs so much space here that chemist-derivatives or the like must be shelved indefinitely until those additions are complete.

So let's go back to your concept. Since you already know my stance on an occult healer (particularly one whose style involves hexes, drain effects, and augmenting its patients), I'll hold my own advocacy and approach this without agenda.
You're discussing a job that, by contrast to other suggestions in this thread, simultaneously would have no formalized concept of science or medicine and instead uses folk remedies bolstered by an unnatural ability obtained from victims of exposure to Black Rose... but also studies a plague nobody else understands, enough to be the prime authority on its applications and replicate its effects in a manner that its use isn't harmful to themselves (and even lacks the "reluctance" to weaponize it), and utilizes chemistry -- not just "eye of newt and toe of frog" brewery, but processes like "synthesis, adaptation, or whatever else"?

Yes. The idea is that some may have some education in Sharlayan, Uldahn, or whatever other arts, but the explanations available with any degree of proximity from those studies of magic are insufficient for the new circumstances, while older, more occult solutions have, oddly enough, seen real value -- leading to an altogether bizarre environment for study. So, some will have no readily applicable formal education, and thus take new paths. Others, perhaps even the majority due to the more reputable scholars having wealth enough to flee in time, have no formal education, applicable or otherwise. You end up, therefore, with a new breed of doctor for the bleakest of times in the bleakest of places. Can an actual Scholar job come in and finally find means of not only circumventing or exploiting the effects of the plague but also how the plague works? Absolutely. And I'd love to see the job quests for that. Are there probably some actual Scholars still in the city, having blocked off the miasma completely? Probably, but such would limit their willingness to traverse much of that zone. Likewise, could a WHM start purifying and fortifying aether or making safehouses sourced in small locations by our XIV equivalent to the lifestream, and survive longer in the miasma due to their infused/innate surplus aether? Absolutely. And Astrologians? Where a truly ominous take on this 'plague doctor' or 'auger' or whatever job might go so far as to disembowel rival gangs to read for signs of the miasma's flow, what could Astrologians instead read from the twisted sky? Who knows? Astrologians would probably be outright new to the zone, seeing as they're unique to Sharlayan and Ishgard.

Doesn't that seem somewhat contradictory?

Honestly, no. I've not described them as idiots just by working outside the techniques of formal schooling. I described them merely as pragmatists, and sometimes opportunists, working in a very new, isolated part of world where everything has been turned on its head.