I'd like a genuine support role, although I'm not really sure if it would operate well with the way FFXIV works with its battle design.

With how many cooldowns tanks have, with how many powerful OGCD's and GCD's healers have access to, and the fact that any useful buff would only be something that increases DPS... it would probably play like a watered down DPS at the end of the day.

Since, as the nature of a support role, they generally are balanced to deal less damage than their DPS counterparts in most MMO's, and in XIV there's really no purpose behind offering bonus healing/bonus mitigation (most of the time). All they'd provide - that players would likely see as useful - are large DPS buffs, and those buffs would have to be large enough for the class to be taken in the first place (as, otherwise, there's no point in taking a Support over an extra DPS). Which, to that point, would basically make it just another DPS class with low personal damage output made up for by it's group contribution (And... providing just a push-and-forget damage up ability isn't really what I'd consider a Support in terms of the role/class design).

Almost all of the previous support concepts in XIV were phased out at this point. All of Astro's cards only provide bonus damage for a reason, even if I still preferred the interaction the cards had back in Stormblood (at least. Effects themselves were pretty niche, but being able to consume them to make another AoE, or increase it's effectiveness, etc... was kind of cool + time dilation). There's also not a lot of use for dispels in XIV, even since StB I can really only think of 1 fight where a dispel was relevant to have and use. Extra mitigation, maybe? But even then, it'd still feel little different from a class with addle/feint/tactician/mantra/crest etc...

I think, among DPS at least, the class with the most non-Damage related utility would be DNC between Curing Waltz/Improv/Shield Samba (not counting shared abilities - though I don't remember offhand if Shield Samba does anything different than tactician/troubadour).

But, ultimately, there's not really a resource in XIV that matters more to people than damage output. The change to AST's cards to all be the same card kind of speaks to that. So, a dedicated support role would end up feeling more like... a bad DPS, essentially. Or just a DPS.

I'd say BRD/DNC are likely the closest XIV will get to a support class, even if it's ultimately just a DPS class that doesn't really interact in a way more traditional support classes would. Granted, to be fair, support classes were generally difficult to find a healthy balance for (either they were too weak and not taken, or too powerful and too required).