1) In case you've magically forgotten, MSQ forces you to go through 9 dungeons and 4 proto-trials for 2.0 story, alone. Yes, you are to tackle multiplayer content. And you're the one hiding behind that excuse so... yeah, my point stands quite strongly actually.
2) Now that trying to appeal to "what everyone does" doesn't work for you, you're hiding behind "what the dev" allows. Allow me to put you out of your misery. Devs are not the comunity. What the comunity agrees and what the devs think are NOT the same. And if you asked many of us, you would find that few players look kindly on the skip potions not having any measure to ensure the skippers do so completely oblivious or that pèople just refuses to make use of what tools there are, either in-game or from outside sources. And GNB scenario does show you the ropes because they DO tell you what your mitigations are, to activate your stance and to use your combo, including cardridge combo during it's course. They do teach you the ropes. And this is why me and many other people bother speaking up when someone messes up so, even if they didn't go through all those resources, they do get the chance to learn.
3) The amount of things you've pulled out of your ass is an hilarious demonstration on your ignorance of what's there at level 50. Because half of those things are not from there to begin with and the other half you don't really know. The fact you're talking about the Moogle nerf shows you only synched for Hard and not for Extreme. And I would need a hundred of hands to count the amount of times newbies unassumedly queue in on an EX trial from ARR and, unsurprisingly, they wipe the moment they ignore the filled in mentors advice because, for being a braindead cakewalk, sprouts sure are usually clueless to do simple stuff such as "not moving while floor slippery during Shiva Ex" resulting in countless of sprouts touching the wall of "turning into an ice pop". And all roles get the minimum tools needed for each to perform their jobs: role actions, tanks get also the 30% mits and their invulns, healers get at least one GCD, even if WHM's is Bene, and DPS get their base rotation and, save for a notable exception, some more. More than enough to get a grasp on how game plays. And if synched EX runs tell anything is that you can't just plow though every content through brute force, since every single one has a mechanic that ensures wipes if people isn't trying to pay attention to the mechanics. Every. Single. One. And this one is an easy tell for someone who gets them every now and then on mentor roulettes and has to run the sprouts through the mechanics. And, while I won't elaborate much, I could build a strong case on how learning many of the EXes mechanic is useful for future reference, it has no bearing on the current argument.
4) Devs also think healer design is ok and regaled us with this xpac's MSQ. Does the community agree? Not really. So.. yeah, I could wipe my arse with the dev intentions, honestly. The fact the community still walls to wall as far as they can even after the devs tried to impose walls is proof enough to tell you how little dev's opinion on how the game should be played matter.