That is one thing FF14 did well - the game teaches you the mechanics language as you level up. Whenever the game throws a completely new mechanic at you, it typically does it towards the start of the fight or midway through it (ultimates/savages being exceptions) or it introduces a softer version in the dungeon for that patch series so you at least begin to learn what the tell means.
The updated 7.1 Hall of the Novice teaches you now all basic telegraphs. It also gives an updated +30% XP ring up to level 60.
For years Blizzard insisted on the "every boss is unique" idea. If you pay attention in dungeons, you'll notice that the trash mobs leading up to the boss have simplified and softer versions of the mechanics. However, this does not work for some bosses, and in most cases players just don't pay attention to trash mechanics in Normal/Heroic/M0, and only start to manage them in higher M+ keys.
The gist I got is the M+ team is deeply entrenched (via eSports elitistjerks culture that's run the design the past decade) Ion has little authority to change anything without them agreeing. He can kick the tires and hold meetings with them, but when the entire team tells him to shut the fuck up, he shuts the fuck up.
According to Occam's Razor, my personal theory is: Ion got Peter Principle'd into his current position as a game director. Either because he is most senior from the ones left, or he lawyer talked himself into it with management. Now that he is responsible for the game as a whole he is overwhelmed by all the spinning plates and just barks commands to his underlings. There is a high chance that all those promises he gave in interviews never made it into "official" requirements and requests to the teams that had to implement them, and the team learned of those promises from the interviews, if at all.
For example, the "reduce healer healing" + "reduce tank self-healing and sustain" came into the equation because healers complained that they a) had nothing to do with the tank, and b) that damage is very spiky and quick, and healing is more like playing whack-a-mole trying to keep everyone up without any of their oh-shit-buttons being able to save players from mistakes. However the memo WHY those changes were implemented on the combat side never made it to the encounter designers and the M+ team.
The core issue at Blizzard seems to be that no one has a coherent vision for the game as a whole and where it is going. Ion, coming from a raider and raid encounter designer background, just seems to care about funneling players into his raids so he can congratulate the top 0.1% players who win raid world first. He doesn't seem to care about the health of the game as a whole, as Ions goal are raids, and he ignores the other parts as much as possible. Well, except when he needs a pull to up those casual end subscriber numbers, because somehow those people finance all this stuff. This seems to be "housing" at the moment.
