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

[MikkoAkure]

I'd consider ARR to have plenty of nuance and it was very clear to me early on that there was more to Garlemald and the Ascians than initially met the eye as is often the case with a great many antagonists in various forms of media.

Not true.

The writers themselves said there was no lore or motive for the Ascians than being generic bad guys from ARR through Stormblood.

Even back during A Realm Reborn, Heavensward and Stormblood, it was said, ‘We don’t have detailed lore yet for what the Ascians’ goals are, so let’s just have them be doing bad stuff in the background

This stopped being true as soon as 2.X patches started.
Elidibus was introduced very early and this was the first hints there was more to the Ascians than just a dark cult.

The ARR patches are also where we get figures like Nabriales who were super into “one true god” and all that.

The truth is that the writers had no idea where the plot was going and were writing it as they were going along. There was no master plan or moral ambiguity beyond just keeping some things vague for later. Elidibus was still 100% for Calamities and killing everyone, he was just nicer about it than the others.

A lot of the lore in 2.0 carried over from 1.X. Saying ARR had no lore just isn't true. Most of the interesting lore in this game isn't even in the MSQ...
Hell the 3 first city states had more lore than the boring shit like Thavnair that came after.

There was enough that was lost or thrown out in between 1.0 and ARR that I consider ARR lacking.

The origin stories for the races being in Eorzea as well as lore bits like their personalities disappeared or were retconned. Most of the plotlines were tossed. Ul’dah and Limsa’s came back a little bit during later quest lines like ALC and MCH but stuff like the main whole mystery got retconned as “it’s an Allagan PvP map now”. Whole swaths of land that had their own lore just disappeared.

As someone who gets really into lore stuff, there’s never been as much as there is for a lot of other fantasy RPGs and the world building has always felt reactionary to where the plot needs to be at any time.

Thavnair is a good example because during ARR and until EW, all but 1 Thavnairan NPCs were Hyur but all of the sudden it turns out there’s been Au Ra there this whole time, which makes things even more awkward for Yugiri hiding her face since there’s been Hannish traders in Limsa since the beginning so Au Ra wouldn’t be strange unless they never left the island and only Hyur did.

[Rolder50]

The truth is that the writers had no idea where the plot was going and were writing it as they were going along. There was no master plan or moral ambiguity beyond just keeping some things vague for later. Elidibus was still 100% for Calamities and killing everyone, he was just nicer about it than the others.

Turns out if you keep the plot vague enough, you can get to an ending and make it seem like that was the plan all along!

[Vyrerus]

Even back during A Realm Reborn, Heavensward and Stormblood, it was said, ‘We don’t have detailed lore yet for what the Ascians’ goals are, so let’s just have them be doing bad stuff in the background

The key here is in the qualifier, "detailed." They had outlines and ideas. Like almost every long running bad guy, there's always something more going on to be revealed later. And they were not shy about dropping stuff for us to wonder about. Chekhov's Guns everywhere!

In 2.0 itself there was the old, universal language revealed by Lahabrea. There was the distinction between Black Mask and Red Mask. There was Ascian possession and dark crystals. Mentions of Zodiark. And the Echo flash to the dark mothercrystal (this one was the only one completely discarded). Their being responsible for The Calamity.

2.1 forward introduced Elidibus. The idea of the Emissary. White robes. The Echo allowing understanding, Hydaelyn's protection not allowing them to take over Minfilia's body. The separation of soul from the body using The Echo. Powered up / hand in teaching summoning rites.

The introduction to The Interdimensional Rift. How to kill them with White Auracite / Blade of Light. Teaching Ysayle she could become Shiva in primal rites.

Exactly where they were going with it? No. Exact history and goals? No.

But the loose plans for bigger things and that history and goal? Yes.

ARR had a structure that pointed towards where things could go potentially. It evoked a sense of wonder. Whereas Endwalker directly instructs you to wonder, cause it doesn't trust you to think for yourself and doesn't want you to, either.