The kind of damage Dawntrail did to this game isn't the kind of damage that can be undone easily, people have already raged and are for the most part bored talking about it, most players stopped caring and stopped being invested in the game's world, and XIV relies on that a lot as its actual game content patches more often than not come up lacking.
I would go so far as to not just throw it all on Dawntrail's feet either. The game has had glaring issues that people were willing to overlook for pretty much it's entire life.
Class Design has been wildly inconsistent the entire time. PLD having Flash as their AoE, MCH being ass nearly forever, the constant class changes to PLD, BRD, DRK, SCH, and pretty much every class being constantly "fucked with" is just something they've never figured out. Every patch is the patch that's going to "figure it out" and then it's just +10 POT here, +15 POT here and done deal. Class differences within roles are
really small and generally come down to one or two signature abilities (like WAR's Bloodwhetting or WHM's Holy) and they basically gave up on Class Lore in Shadowbringers. Nearly every class having a 2m cooldown is very boring but also feels like it's carved in fucking stone over at Square.
Gear design and implementation are also really really bad with the main innovation being "No more Belt Slot". Relics are the worst offenders because they take so much effort and are deliberately gated to not be useful in raids - there's literally 0 reason to not have the final step do
something. The gear disparity is massive from early patch to late patch for virtually no reason and all of the gating in gearing feel pointless unless you're actively raiding (and even then, the Tomestone gating feels pointless). All of this for very minor stat upgrades that math out to fractional percentage points.
Leveling is generally very boring and constantly having the classes get "fucked around with" as you level makes a lot of the experience feel very inconsistent. MSQDR still existing is insane.
Crafting and Gathering classes have no soul or identity (except FSH) and have had basically 0 innovation in 10 years. Just a fairly boring and mainly automated grind that you still need to repeat (and equip) 8 times over. Having gear tied to a single Crafting class is a
colossal waste of time and effort and I have no idea why they still do it on 50%+ of the scrip gear or why they still have such a boring scrip system in the first place.
The majority of the game (and patches) are largely just "go here, talk to X, go to Y, talk to Z" and repeat for a few hours with a token fight vs a single random mob being thrown in for good measure. It all leads up to a single dungeon and/or trial that always drops the same level of gear (which is always worse then every other source of gear). While some of the writing and concepts are cool, they very often meander and waste time.
And PVP is well, PVP.
Dawntrail obviously didn't fix anything (and actively made some of it worse) but it's main crime is being bad enough to look at the game and think "has it always just been this way?". For me it did, at least.