Holminster Switch worked because the game built up the consequences early on. The mystery that something very dangerous was happening was established in Stormblood, and we constantly feel like we're racing against the clock for the rest of the expansion (made evident in Amaurot's theme song and To the Edge). We first start Shadowbringers learning about the desolate world we're in. We're told to go to Eulmore and we see what desperation, giving up and privilege do to a society. And then we go to Amh Araeng and we see the last dredges of society barely holding on by a thread. Tesleen is trying to help victims of Sin Eaters who are slowly turning into them, but there's no hope and all she can do is ease their pain until the time comes. Out of nowhere, she's assaulted by the Forgiven Dissonance and turns into a Sin Eater in front of Alisaie. The small village of Holminster is attacked, and though the first thing we kill is the Dissonance and get catharsis and revenge out of it, the second boss is Tesleen herself. Alisaie goes silent.
There was a build up. You're shown plainly what the dangers are, the tension is all over the place because almost nowhere feels safe, you see the world crumble right before you and it even scars Alisaie. Tesleen was the loss, and while a minor character, it's made clear that Alisaie truly cares for her and her becoming a Sin Eater was a violation. Tesleen was the stake, and it makes us realize that anyone can become a Sin Eater and end up just like her. We see the dangers unfold before us, in a personal note.
The Vault happens in a sequence where the only real tension is Thordan being a jerk. Animosities with dragons were slowly clearing up and people were starting to realize who the real danger was. But Thordan reveals himself to be power-hungry, ignoring even his own son's plea for sense. We knew that Thordan wanted power, with the Heaven's Ward under his pinky and having been established before to be unscrupulous and antagonistic. The dungeon starts with an organ mix of Ishgard's theme "Solid" called "Hallowed Halls". The cutscene actually starts with echoing gothic bells, usually associated with mourning in media. But as it goes on, the main melody of Hallowed Halls starts to drop to a lower key, in a very funerary and somber tune. Then we finish the dungeon, where Haurchefant shields us from Zephirin's spear and he dies.
Again, though there were no narrative indications that he'd die, the dungeon itself does a good job. It blends both the scenery that we've come to expect from Ishgard and a tonal expectation that's subtle in the music. As you keep going forward, you slowly start to realize just how much of a threat the Heaven's Ward is and it dawns on you what Thordan is capable of via the bosses. That last one even makes it clear that he doesn't value life, only hierarchy. And when someone close to us dies immediately after, it validates what the dungeon was establishing and makes the consequences real. It makes our conflict with Thordan far more personal then than before.
Vanaspati was brilliant in that it reminded me of Holminster Switch but on a second thought it kind of falls flat? As I said, HS starts with the personal note already being there for you and Alisaie. The first boss is a vengeance quest, while the second one is an emotional gut punch. But while Vanaspati is scary because of Vrtra's voice-over where you hear his laments and the music is intimidating, to many players the real impact of the dungeon is the woman with her children. A replica of the incident at Radz-at-Han. For us, it's shocking and scary and it definitely sticks in our minds... but there's no pay-off to that. Vrtra already made it clear he's uncomfortable; he doesn't comment on the mother's death and the children turning as well. We never even get to know who the mother is. There's no personal connection to be made for us. It's just glorified violence for shock value, to make the Final Days live up to their name.
Past that though? It's just... there. Implied in the background. And the Job Quests. The Final Days affected no one in the main cast, with Vrtra only really lamenting over faceless NPCs. Sure, it's sad, but for us we don't connect. We don't know these people. The sadness we feel is the generic loss of life: sad, but that's all we can really say. Ultima Thule gets a lot of crap for the same reason. It's trying to build up such a reaction from us, and it almost succeeds. Thancred's gone. Not just in that "he disappeared", but he also "became the light for us to see where we were going". And it's scary at first, but then you expect to know more about this, but no, you just move on. Then it's Estinien's turn, and he also "dies", but it's more visibly heroic rather than shocking, and we can't help but wonder "what's going on" since they're all dropping so fast. And no soon after does Y'shtola come in and flat-out tell you "Yo, there's a way to bring us back, just don't use that method at the wrong time!"
And that's it. It cheapens out the rest of the sacrifices. Great for character development and establishment, but it just invalidates the sadness in seeing them go. There are no stakes for us. We have no personal emotional investment in the characters we see depart. And when we do, the story tells us to relax.
I'll be honest, I had more of a visceral reaction from the Blades in Delubrum and knowing Dabog's fate in Zadnor than I had about any of this. Because despite them being background NPCs, I THOUGHT they were going to be major players and actually had time to read about them and took time to wonder how they felt about all that was going on. Vanaspati isn't a dungeon I remember for the emotional impact, but for the shock value. The Final Days didn't feel like a race against the clock, because the stakes were so localized and the plot armour our friends were wearing was so glaringly obvious. Had I gotten more information on the mother in Vanaspati, surely I'd feel the impact a lot more than "wow, this is harsh!!". But I didn't. That execution was never there. And for a fate just as bad, if not worse than the Flood of Light, it felt quite flat. And speaking of music again, the first time you hear Insatiable, it's dark and you can tell that the fight is a cruel one in an unforgiving world. Endwalker's "Finality" is too heroic and upbeat in comparison. The mid-boss music "On Blade's Edge" does a better job at it, but even that has a lighthearted tone.
You know it's bad when the only NPC that we emotionally connect to and that we visibly see being affected by all this is Matsya. And nothing major happens to him, he just nearly turns with a baby in his arms, but then gets Vrtra Ex Machina'd and he's alright.