Good examples. I liked all of these things as well.

But it felt like I was one of the few people who even knew all of these things sometimes so I can sort of see why SE tried to make everything "super obvious" to new/casual players.

Even now I do dungeons like Xelphatol or Sohm Al HM or Halitali HM and don't see tanks drag them to the vulns. I feel like it would be satisfying if we were playing a game where a lot of players had a mindset where they looked out for stuff like this, looked at status effects, casts, observed their surroundings and made guesses, read things, but it's always just gone over the head of most dungeon players that I've seen, particularly in older dungeons, because there is a huge abundance of people with other interests like glam, RP, social interaction, hanging out, story, that don't necessarily involve optimizing things or trying to make smart decisions.

I can throw some other examples though:
  • Saint Mocianne's Arboretum HM has water that you can turn on and drag them into. Plus mob AoEs that turn you into a plant.
  • Shadowbringers dungeons have various interruptable casts on trash - which of course, players ignore giving more work to healers.
  • Aetherochemical Research Facility has healers that used to be really annoying, and casters that could turn you to stone, so you could decide which of these things was most annoying and prioritize one.
  • Neverreap, much like Qarn normal, has bees that do Final Sting so you can make them priority, kill them first via a single pull, stun (or time Holy) or time invuln or have faith in your party DPS.
  • Pharos Sirius has a way to get lost that gave you vulns whereas you can optimize by knowing where to go, reduce the chance of wipes by your decisions with the mists and knowing how hard certain packs hit, things in the HM explode so you can optimize by getting in front of it faster, there is a giant breaking down a wall that you can pull or not, etc.
  • Lost City HM I recall we focus the light elements first and some of them had gazes that of course most players just look at and get debuffed.
  • Hullbreaker normal has traps you can get caught in and get a deadly DoT, the HM has a mob drop puddles and if you stand in it you (at least used) to be close to dead, the enemies at the end had various gimmicks and status effects so you could choose who was priority or your strat.
  • Baelsar's Wall had NPCs that tether to you, and one that applies DoTs (such as to the tank or healer I recall). So you could make this priority. Some of the garlean machines all do their AoEs at once, so you could reduce the healer burden by stunning one.
  • Mini-boss mobs in Sirensong Sea that you can interrupt to make them easier, and one of them you have to choose the right cast or interrupt is wasted.
  • Bardam's Mettle there is a bird that applies a devastating DoT. It always helped healers to anticipate this DoT, either with mit, stuns, or whatever other strat you had for it, and made the big pull safer.
  • Dzaemael Darkhold where the frogs are where we got knocked off in the past, one of them still applies a vuln to the tank. That vuln instantly makes you die to damage unless you invuln or it gets Esuna'd. The tanks that don't know either die or get saved by good DPS or a good healer that Esuna's. You can also do a gigantic pull from start to first boss, because the purple area mitigates so much that you don't even need a healer (literally did it without a healer on WAR), and that's due to the gimmick of the dungeon that many players aren't aware they can do.
  • Dungeons with morbols that cast Bad Breath (stunable). Especially Aurum Vale! The positioning of them or how to tackle them can affect, well, if you are all sitting in debuffs.