So the tanking model that FFXIV has employed in dungeons has never been one where you've needed to really work for your enmity (at least, not since Heavensward, really - it was a bit in ARR if I remember right, but it hasn’t been the case in a long time). As someone who was a career tank in WoW for many years before making the jump to the greener pastures of FFXIV, this has always made me a little sad. The current state of tanking is one that, while incredibly balanced (all four tanks are viable and function well in current content), is also obscenely boring. It really became boring in Shadowbringers, with the removal of the notion of separate stances for tanking and DPS. Every dungeon is the same: pull as much as you can, pop your CDs in descending order of effectiveness, and AoE until the cows come home while dodging the color orange--and there isn't even any danger in doing this unless you or your healer is severely undergeared. Even dungeons where it supposedly matters, like the frogs in Dohn Mheg, don’t really do much if you ignore the mechanic.
In what I'll call "classical" MMO tanking, tanks had to worry about a lot with any given encounter. Enmity generation mattered. Mob positioning mattered. Kill order mattered a lot of times. Crowd control like long-term stuns and saps and polymorphs mattered (and could make the run much smoother if done right). Interrupts mattered. Overpulling, even when well-geared, was an extremely risky exercise that even the tanks with the best gear avoided. Tanking had an aspect of it that was exerting control over the instance and the encounter, and leading your group in how to best approach a dungeon. A good tank used their party members’ unique aspects to their advantage, and knew how to navigate challenging encounters, and how to adapt to changing circumstances. Classical MMO tanking was about encounter management, and the best tanks were the ones that could manage the encounters the best.
But in FFXIV, none of that matters. You don’t have to work for enmity. You don’t need to have your rogue sap the caster or your mage polymorph the berserker. You don’t have to wait for patrolling mobs that will fork you up if you’ve got other mobs with them. You don’t have to be careful how you pull--in fact, the game rewards pulling recklessly. You don’t have to do much to plan out your mitigation, and half the time, you don’t even need it. You don’t have to be strategic with how you approach a given challenge, if they can even be called that. Tanking, and specifically tanking dungeons in FFXIV, is nothing like what classical MMO tanking was.
And look at the result. Tanking was made much more approachable by removing all but the most basic components of classical MMO tanking, and so we have a lot more people in FFXIV who are willing to try it. The formulaic aspect of just having to hold hate on everything by spamming your AoE combo makes it easier for people to learn how to evaluate the pace of damage coming in, and the best sequence for their cooldowns. They’re able to learn and focus on their rotations while dodging orange markers on the floor with very little that would actually endanger them. For a classical tank who’s used to dancing the line between success and disaster, this design of the game is incredibly boring, but for someone who wants to try tanking out? This design is ideal, because they can try it and contribute to their party’s success without worrying too much about whether or not they’re going to screw up and cause a wipe.
As a result, queue times for the other roles are lowered because tanks are more common, or because more people are willing to queue as a tank. In some cases you’ll still see long queues for DPS, but if you’re in an FC, there’s a good chance that you’ll be able to get someone to come tank for you, where they wouldn’t if tanking was the challenge classical tanks are used to.
The danger with this design is that classical tanks are going to feel alienated, and will gradually abandon the role. Without the stimulation of all of the other things that tanking used to involve, they’ll find it boring and shift to other, more stimulating roles, all while lamenting to their friends that tanking is not what it once was (and sounding like grumpy grandparents the entire time). And they may even abandon the game. Healing is not as engaging as tanking, and the challenge of most DPS jobs is memorization and learning the beats of an encounter to be able to maximize output--trivialities to a classical tank.
Unfortunately, I don’t think there’s a middle ground. Having encounters that challenge classical veteran tanks will alienate the newer tanking generation, and having encounters that cater to the newer generation will bore and alienate the veterans. And unfortunately, given how little the game seems to be built to support more complex encounter designs (based on how comparatively little utility is built into other jobs vs. a game like WoW), the likelihood of FFXIV moving towards that sort of design seems very low to me.
Is there an answer to whether tanks should have to do more classical tank things? I don’t think there is. Making tanking more challenging in the classical sense will make it so fewer people want to tank, but at the same time, keeping tanking as comparatively simple as it is will also make fewer people want to tank (albeit, I’m pretty sure, to a lesser degree).
So, for me, as a bored classical MMO tank, I’ll just resign myself to doing goofy all-tank Expert Roulettes and Trials and Raids with my friends where we can do stuff the game isn’t technically designed to do, and where more of the enjoyment comes from the company I’m keeping than the role I’m playing. Besides, healing as PLD is actually a lot of fun--and I suspect it’s because it’s not what the job was designed for, and so is actually somewhat challenging sometimes.