We also need to remember that these dungeons are for story players that have no idea how to play the game. You will get tanks that barely know how to do anything other than attack enemies. You will get healers that fish for freecure procs in bare minimum gear they got via MSQ.
To show a real world example of how this affected me in past dungeons, let's take the Ala Mhigo dungeon. I once did a giant pull there with a sprout MSQ healer. They were barely keeping me alive due to their gear and spamming cure, and the only reason I lived was because I had tanked for years and knew how to give sprouts ages to heal me - most tanks would have just died with how the game was then.
I felt really bad for the healer, and this used to be a common feeling for tanks. They have to pull all the enemies, because groups usually get upset if they don't, but then they felt (with certain pulls) they were giving healers a heart attack by doing it. And in some cases, the tank would die because the sprout healer had no idea how to handle it.
This is why SE added walls. It's probably why they made tanks have all these self heals to trivialize said pulls. So they are not giving sprout healers a heart attack. But obviously it makes the dungeons braindead for "experts" in an "expert roulette".
Maybe what they could do to solve that is just have 2 routes always, one of which is an easy route and one of which is a very challenging route, and the challenging route can give lots of special rewards. This way a story player could just choose the easy route.
I remember reading about that when I started tanking in ARR and the guides saying to mark enemies 1, 2 and 3. I quickly discovered that was... not workable because there were BLMs casting AoE spells and ripping aggro, and instead spread out my combo attacks because PLD had no AoE.
The enemies hurt a lot more, that is for sure, and especially since many dungeons at that time were leveling dungeons which sync tighter. But I never personally saw anyone bother with Sleep.
Enemy packs have almost always been "sets of 3", so a strategy I learned right away as a tank was to carefully wait for a patrol to move away so I would only pull 3 instead of 6. This used to be useful in ARR dungeons due to them be tougher back then. Eventually, SE taught this in Hall of the Novice - but by then it was irrelevant in every dungeon except Aurum Vale and Dzemael Darkhold.
But this is where all the points I made at the start of this post come in. If you pulled everything in Aurum Vale or many ARR or leveling dungeons, you were giving healers a heart attack and I can't say SE is wrong for addressing that issue.