That is true, I absolutely loved SCH in FFXI, it was a fun healer / DPSer; not the BEST, but it's set of tools made it effective; it's probably why I don't play SCH in FFXIV, bc I loved it so much in FFXI that it's design here is so, idk, just not what I, as a player, envisioned bc it was warped by FFXI's great design. It goes with GEO too, FFXI's GEO was neat too, not revolutionary, but fun nonetheless.
I believe FFXIV could make a fun, unique GEO, that could fit with its current cookie-cutter framework, instead of "Holy", give it "Quake", instead of "Stone," give it "Water," instead of "Aero," give it, "Thunderstorm," and then fill in the gaps with its healing spells.
Back to Chemist, if put some effort by the Dev. team could be made fun, but they'd have to make it simple enough to where it's not a burden when healing.
Imagine having to Brew a powerful potion when a tank gets a tank buster and your instant mega heal is on GDC? Let's say, X-Potion is that OGCD (Benediction / Essential Dignity) move? He'd have to Combined 2 Super Potions to create a Mega Potion, pop the tank with it and hope he's not dead! While the other caster healers just pop a cure spell. But, since the CHM technically has no "cast time" they could fire 3 Super Potions at the tank before a caster can pop a cure.
Idk, this is all for fun! But I think CHM could work really well.