What's the point with that quite lackluster story in Endwalker?

[KageTokage]

The Ancients would never manage to fight Meteion because they were so powerful and full in Ether that they would not be able to manipulate (or be manipulated by) Dynamis.
It's why the Scions had the perfect balance to both manipulate Dynamis by using their ether to create the various places in Ultima Thule.
That inherent weakness was one of the reasons of why Venat chose to sunder everyone.
The second reason was also to make humanity weaker, so they would never be able to achieve perfection, which could also be destructive as we see from the Ea and other races that simply lost the will to live after reaching Utopia.

Her actions are not presented 100% in the right btw, and this is commented on both by the story and by her when she asks for forgiveness. But it was the best she could do, if the Ancients continued their ways they would simply all die either by Meteion or the other dangers I stated.

People have already argued and debated at length about how flimsy Venat's stated reasons for carrying out the Sundering were to them (Hence why this topic has bloated to hundreds of pages among other causes) but...I'll bite.


Dynamis

She admits to having only a "basic" understanding of dynamis back in Elpis, and she tells literally nobody the whole truth of the Final Days, not even her own followers so unless she somehow determined for herself off-screen that there was absolutely no way the Ancients could've solved their whole dynamis debacle (Which was started by an Ancient's creation in the first place), it feels rather poorly reasoned to me, particularly when she's only educated about the negative effects it can have on people. Any positive uses for the stuff would've been strictly hypothetical.

Death by perfection

Seeking perfection in itself is not dangerous. It is the reckless pursuit of perfection that is cited as being problematic. The Nibirun sought perfection through elimination of strife and cast off so much in the process that by the time they reached that ideal, it was so hollow that Meteion's simple question was enough to convince them to give up on life. The Grebuloffs desired more and more and followed the path of conquest only to destroy their ecosystem in the process. The Karellians simply got into a prolonged war that kept escalating further and further until both sides ended up destroying one another with WMDs. The Ea...didn't really do anything wrong at all, they just couldn't handle the "ultimate truth" of existence; that all is seemingly destined to eventually end due to the heat death of universe.

The Ancients were not a reckless people. They spent an extremely lengthy period of time debating about the morality/necessity of the third sacrifice, and it got to the point where Elidibus had to force himself out of Zodiark to enact his role as a mediator just to help them to finalize that decision. The notion of them simply choosing to collectively off themselves if they ever somehow managed to truly achieve "perfection" feels a bit...preposterous with how meticulously they'd consider any decision that would affect their society on a larger scale, coupled with the fact that they sought perfection through addition, not elimination like the Nibirun did. While they did intend to sacrifice surplus life to free the souls within Zodiark, it was something that the Conovocation had deemed would be for the greater good, and rather logically so considering that 75% of what little population that had survived the Final Days was now trapped in purgatory.

Weakening humanity and inviting strife and conflict into the world has opened them up to far, far more "dead ends" then they were vulnerable to pre-Sundering, and Meteion was never going to be an issue as long as Zodiark was intact considering he was still doing his job for 12,000+ years after being sundered.


As far as her actions not being presented as entirely in the right goes...it's literally only called out by the Ascians and herself due to the admittance of there being "no justice or kindness" in it, and it's one of the chief things that bugged me about Endwalker. We're allowed to express doubt towards her when we meet her on the way to Old Sharlayan and question the morality of sealing Zodiark in Mare Lamentorum after seeing the Ancient souls mourning and suffering within him, yet when we finally meet her in person as Hydaelyn, there's nothing but unanimous positivity. It's only in the Omega quest post-MSQ that we're allowed to actually inject our own feelings on the matter, but it felt a bit...hollow versus telling it to her personally.

I can agree that her methods did work, but being able to at least question her about it truly being the only/best option available would've at least left me feeling less emotionally dissonant without having to drastically change the story.

I was really expecting the Sundering to be extremely well-reasoned, like as an act to prevent the immediate end of humanity, not to spare them from some hypothetical "death by perfection" some point in the very distant future.