During the media tour for Dawntrail Yoshida mentioned these lore bits

[MikkoAkure]

You'rei assuming the remaining Ascians would do things that make sense, case in point: All of Fandaniel. I don't think it's likely in any case, but it's not outside the realm of possibility. Until we've seen them or have discovered their fate in one way or another, they are loose ends.

Another piece of my point is that this is a constructed work of fiction and to retread the same tired plot again and again would be boring.

The main point was that you have to do a lot of mental gymnastics to convince yourself that it looks like an Ascian Glyph, when we've never seen any Ascian Glyphs that would have to be so ridiculously distorted to look like that. They've been ripped directly from FFXII. As for the other fighters you seem to be under the impression that they will all be player races when there are in fact a whole bunch of sentient races that look more like monsters than humans in FFXIV such as all of our Tribe buddies.

It doesn’t really take a giant leap of logic to make it look like an Ascian glyph. It has all the same elements of the bottom of Ultima’s symbol from FFXII flipped upside down like how all of the other Ascian glyphs are elements of upside down esper symbols. The only thing that makes it vague is the fact that instead of being perfect 1-1 it looks like it’s been run through a photocopier too many times.

A distorted symbol of an Ascian appearing over Solution Nine is a much more interesting theory than a distorted symbol meant to evoke a forgotten, skippable boss from a past game. And in my mind it’s more plausible too when we know there’s already an existing Ancient connection to the likely location of Arcadion. This art doesn’t exist in a vacuum and is meant to tease the playerbase about the upcoming raid. I don’t believe that something like this that they bothered to place in the background and then partially copy down below as well in the teaser artwork would amount to something trivial.

As for the enemies we’ll be facing, not once in my post did I say they’d be player races. This is a raid so the enemies we’ll be facing will be scaled up as always and have some sort of artistic flair, but I think the idea is that they’d be at least sentient beings and not outright monstrosities and my hope is that they don’t pull an Omega and just rip random mindless bosses from past FFs and paste them in with 0 context or point other than “this part of the raid is FFV bosses, do you remember this reference?”.

I never posted that claiming it 'debunked' anything

This was what the poster above was claiming.