Dawntrail's Final Zones destroy everything the story has built.

[Lady_Silvermoon]

An extra possible plot hole to add to the pile.

What happened to Erenville's mom when we turned off Endless? Did the soul that was used returned to Aetherial Sea?

We know that when the soul returns there, it regains all memories. It can undo memory alteration since it undid Emet Selch and Hydlodaeus memory wipe. If so, the soul that was used for the Endless regained original memories, and now has implanted memories on top.

While the real soul from which memories were taken has no clue about what happened after its death whatsoever.

In other words, the Endless really did not do anything after death, did not meet relatives or dealt with unresolved issues, all this process did just dumped some fake memories on unrelated souls.

Because the souls they used have been arguably "deep cleaned" in their own factory version of the aetherial sea, there is no longer a person attached to the soul to be reasserted as the owner. If Origenics process wasn't more thorough than the aetherial sea's then people's personalities would change every five minutes as they used souls as powerups. So more than likely the people who were walking around in Living Memory returned to the aetherial sea for their current memories to be washed away in the usual process. While the 90% of them who didn't have souls to graft onto just dissipated immediately. Also, Erenville's mom should be in the aetherial sea on the shard we were on, so I have no idea why he expects to one day see her and speak to her again, even if she spent centuries trying not to be washed away by the aetherial sea just to wait for him, she's in the wrong aetherial sea...and her original soul is probably a coin somewhere in Everkeep. Not that which soul you have makes any different once they invented their own aetherial sea and have been swapping souls like hot cakes.

Honestly, the lore is extremely brutal to creatures that "don't have a soul". All of Elpis is basically the Ancients messing around creating and destroying life for fun and science, and only Hermes seems to have any sort of empathy or compassion for these creatures.

The animals in Elpis have souls. After Hermes kills the beast, we watch it's soul return to the aetherial sea. He even talks about it's soul. DT has now confirmed their are both people souls and animal souls. It seems that everything on the star has souls except for familiars and elementals. But soul or not, I don't think we should mistreat sentient beings.

[Nadda]

The animals in Elpis have souls. After Hermes kills the beast, we watch it's soul return to the aetherial sea. He even talks about it's soul. DT has now confirmed their are both people souls and animal souls. It seems that everything on the star has souls except for familiars and elementals. But soul or not, I don't think we should mistreat sentient beings.

I believe the important part about the mistreatment of sentient beings is that Living Memory is in itself mistreating sentient beings on two fronts.

By keeping the memories of the deceased with residual Aether, keeps people from passing on to the Aetherial Sea as they are intended to go, so you're mistreating people's lives by having them live half lives where they can never die even if they wanted to.
Secondly much like how summoning Primals in the source absorbs the Aether of the star it negatively affects the living beings around it because that Aether that is normally recycled and equally distributed back can no longer do so.
This is why this reflection's attempt at assimilating other shards (not unlike a rejoining) is a fruitless effort, there will never be enough Aether to sustain all these people, there will be a constant strain on the living world until the whole thing collapses in on itself.

The idea of having the living die so that the dead of that shard can live on more borrowed time won't help anybody.

Now ultimately if Living Memory operated more like how the Ancients themselves would voluntarily pass on that would have been great. However it would appear as though these Endless don't have that capability. They have the Memories of the deceased but are not entirely the deceased. This probably explains why we can't taste the food in Living Memory... because it's all synthetic. To the Endless that popcorn or ice cream will taste like their favorite memory of such snacks but to the living they offer no nutritional value whatsoever.
I feel like 7.x story will continue to explore this realm's potential. I was surprised for example that we didn't make use of an alternative power source like Dynamis - but alas.

[Lady_Silvermoon]

I believe the important part about the mistreatment of sentient beings is that Living Memory is in itself mistreating sentient beings on two fronts.

By keeping the memories of the deceased with residual Aether, keeps people from passing on to the Aetherial Sea as they are intended to go, so you're mistreating people's lives by having them live half lives where they can never die even if they wanted to.
Secondly much like how summoning Primals in the source absorbs the Aether of the star it negatively affects the living beings around it because that Aether that is normally recycled and equally distributed back can no longer do so.
This is why this reflection's attempt at assimilating other shards (not unlike a rejoining) is a fruitless effort, there will never be enough Aether to sustain all these people, there will be a constant strain on the living world until the whole thing collapses in on itself.

The idea of having the living die so that the dead of that shard can live on more borrowed time won't help anybody.

Now ultimately if Living Memory operated more like how the Ancients themselves would voluntarily pass on that would have been great. However it would appear as though these Endless don't have that capability. They have the Memories of the deceased but are not entirely the deceased. This probably explains why we can't taste the food in Living Memory... because it's all synthetic. To the Endless that popcorn or ice cream will taste like their favorite memory of such snacks but to the living they offer no nutritional value whatsoever.
I feel like 7.x story will continue to explore this realm's potential. I was surprised for example that we didn't make use of an alternative power source like Dynamis - but alas.

Yes, I understand why Living Memory in its current form is unsustainable. However, we've been in contact with a number of immortal species whose existence does not harm the environment. And while I agree that forcing people to exist against their will is wrong, I also believe erasing people from existence against their will is also wrong. Out of the handful of people we meet there, three express the desire to be erased. The man eager to marry his fiance after centuries probably could have used a few more days. Some even have unfinished business we have to resolve so they can dissipate. Some even express hopes for the future. They were not all ready and willing to be erased. And I don't think beings should be forced out of existence because it's what's "natural." All the people there wore regulators knowing what they were and what they did, so while I agree the people who want to be set free should be set free, it's unlikely the vast majority of these people are being held against their will given they had to agree to have their memories tampered with to even end up there.