They both had both, the MP refresh on MCH was tied to the AOE turret though in HW (promotion), in SB it was changed to role actions (Refresh and Tactician). They also had stuff like Palisade (ST phys mit, foil to the caster role's magic mit), and Troubadour, Minne and Warden's (the esuna thing) both existed as far back as SB, etc. MCH was a lot less focused on having 'support' style utility compared to BRD, but it did have the basics of MP/TP restoration potential, and a way to increase damage dealt by allies via Hypercharge. Which is why I find the whole thing about 'what if support was a role' kinda extraneous. We either already have it (as Ranged) or we already have it (as Healer), there's not really anything that a 'true Support role' can do without cannibalizing what we have already, or just renaming some of the current Jobs we have now to the new role, just to pad out it's roster and justify it's existence. If we were to, for example, add a new caster that is 50% personal damage, 50% comes from various raidbuffs, and it's got loads of wacky support skills like a CD that heals allies, a couple of ways to apply mitigations, an AOE Esuna cos why not, a res, etc, then I don't see that as a 'Support', I see it as a 'very support-tool heavy Caster DPS'. We didn't call NIN a Support back when it had Shadewalker, Smokescreen, a Bind on Hyoton (yeh that's still a thing, surprisingly), a movespeed slow on Doton (still a thing), Trick Attack, Jugulate to stun or silence. It was a Melee, that was very support-heavy.
As for WOW, they've more recently moved towards 'scripted big damage moments' too. Difference is, they have smaller ticking instances between those big blasts. For example, a boss I hated reclearing each week from the first raid in DF, Terros. Players are marked with markers, and they place earth spikes after a few seconds. While these spikes are out, they pulse damage on higher difficulties, and the longer the fight goes, the more spikes come out (on heroic, it was 5,5,6,6,7,7,8,8, enrage, iirc). To clear the spikes, the tanks aim a line-Tankbuster through the spikes to crack them. Doing so, however, causes the spikes to explode for a much larger amount of raidwide damage. Thus, there's 'constant pressure' from the ticking, and then big 'scripted moment of big HPS needed' to plan your big cooldowns around, like Aura Mastery, Spirit Link, Tranquility, etc. We've got the second half, but not the first half. Additionally, WOW's healers are designed around having basically zero spammable AOE. Closest there is to 'spammable AOE heal' is Chain Heal, and that eats your MP bar like nothing else. I expect that, if we dropped a WOW fight into FFXIV wholesale, we'd fold it's HPS requirements like a pretzel, because we can just dump AOE healing whenever we like. To have 'WOW style model', play WHM, but unbind Medica 1/2/Cure3 from your bar, and only AOE heal with Rapture, that's pretty close to what we'd end up with
Also, I saw some 'very good at game' WOW healers complaining about healer design over there, saying it's getting too focused on 'use mit on big raidwide'. Apparently, having a raidwide that blasts you from 100% down to like 20% is not fun, who knew
And again, I'd say to that 'why add a Support role and screw up the matchmaking/queue times, when we could just make the 'already kinda heavy on support' Jobs like DNC be 'even more supporty'? People who got into certain jobs like BRD or DNC already have an expectation that they're going to have lower DPS, but bring big buffs. So if you give them MORE buffs, then they'll be happy cos it feeds into their expected perception of that job, surely? Well, except the logheads who are now more reliant on their team to do good in buff windows but design shouldn't be based around things like that.
If an announcement was made saying 'AST is being moved from an 80/20 split in personal damage/raidbuff damage contributions, to a 60/40 split, to better capture the identity of 'it buffs allies', who's gonna complain and go 'no I really like how much of my damage comes from Malefic as it is thanks'? There'd be at least one (there always is) but I assume the vast majority would be excited for the 60/40, and a great many would likely ask for more ie 40/60