(Wildly speculative) idea about the next overarching threat - *spoilers*

[Alleo]

My speculation for the next expansion is, that Golbez will fail and that at most we might get some regional destructions on the source thanks to his failed attempt. Why? Because even with the Final days happening in Eorzea the map did not change and I really doubt something so big will happend that it will affect Eorzea and thus the zones. Maybe we get a smaller void invasion in the unexplored regions of the planet which in turn gives us the motivation to travel there.

The void will still stand after these patches imo because the destruction or rejoining with the source would create too many problems. The two biggest: The whole sidequest which is about rebuilding and saving that shard would be for naught. And the reaper job would lose its power because our voidsent would be rejoined.

Other than that I have no idea what will come with 7.0 that leaves a big impact. And honestly I would be fine with just smaller conflicts. I dont need another calamity right after Endsinger...

[RyuDragnier]

This is interesting because didn't the Ascians themselves give up on rejoining the 13th because the balance went too far towards darkness? If the Ascians couldn't figure out a way to rejoin it, how on earth could Golbez figure it out?

Because they gave up on it and didn't bother looking for a way to mitigate the damage, figuring Zodiark could fix it once he had enough power to be freed.

[Seraphor]

My speculation for the next expansion is, that Golbez will fail and that at most we might get some regional destructions on the source thanks to his failed attempt. Why? Because even with the Final days happening in Eorzea the map did not change and I really doubt something so big will happend that it will affect Eorzea and thus the zones. Maybe we get a smaller void invasion in the unexplored regions of the planet which in turn gives us the motivation to travel there.

The void will still stand after these patches imo because the destruction or rejoining with the source would create too many problems. The two biggest: The whole sidequest which is about rebuilding and saving that shard would be for naught. And the reaper job would lose its power because our voidsent would be rejoined.

Other than that I have no idea what will come with 7.0 that leaves a big impact. And honestly I would be fine with just smaller conflicts. I dont need another calamity right after Endsinger...

We're still missing huge portions of the planet, and even the zones we do have, only a small fraction of them are physically explorable.
I'm not saying I predict this would happen, but I think it has potential and I may even like it if it did:

Golbez succeeds at his plan. He finds a way to rejoin the 13th and the Source, in a way completely different to what the Ascians were intending, in a way they never would, because of how catastrophic it would be to the Source.
We get a full merging of the worlds, just like FFV. Zones from the 13th show up in the Source, all over the place. Fragments transplanted into our world. They're in the Shroud, in Thanalan, Coerthas, Othard, but each of those are conveniently just out of bounds or new extra zones. Instead, our map expansion would take place in a new area, say Meracydia. There we see the true impact of this joining of worlds as the new areas are hybrid Source/13th zones.
By the end of 7.0, the worlds are seperated again, and this functionally works out because the 13th-incursion zones were designed in a way that the could be reverted back to purely-13th zones, and vice versa, by changing the skybox and the out-of-bound models. And it works out by lore in the fact that the end of 7.0 finally gives us unrestricted world travel.

[Kesey]

Given past story beats, I'm not sure we are really thinking this out well.

Golbez and fiends are currently on this whole, "I'm looking for the sweet release of death and the death of everyone else" thing, but we heard this before with Fandaniel and it was hugely inaccurate with what he was really trying to accomplish.

Next, we see the all the obvious connections with Golbez, but he is again a masked villain who hasn't given away what his real identity is either. Too many times we've had masked or hooded villain whose reveal is more vastly important for the story going forward.

Unlocking where the next threat may come from is going to require a better understanding of Golbez's identity and what coded meaning he has at the end of each patch.

Unfortunately, I think we are also being left in the dark on purpose too. It's very odd how similar the story beats are coming up, yet they are all void of any real foreshadowing.

[Kesey]

Furthermore, something strange I noticed is we caught up with the twins in 6.3, which has now shown us what every scion has been doing since Endwalker, except for Thancred. Every single one of them is either with the WOL or pursuing another personal interest.

Thancred checked-in in 6.1 and said he was off to scout the far east and hasn't been heard from since. All of his story lines have been ended and he remains the only member of the main cast without a real purpose or goal. Compound this with Yoshi-p's comment about Thancred and Krile carrying the story forward.

What if the reason for the next adventure is that Thancred is missing? And the new area is the Hingashi islands and other unexplored areas of the Far East?

[Cleretic]

Golbez and fiends are currently on this whole, "I'm looking for the sweet release of death and the death of everyone else" thing, but we heard this before with Fandaniel and it was hugely inaccurate with what he was really trying to accomplish.

...except that was exactly what Fandaniel was going for. He even reminded us of it right before he took Zodiark.

Fandaniel was a fantastic character with a surprising amount of facets and my favorite Ascian by a long ways because of it, but at the end of his life, Fandaniel-as-Amon had an extremely simple goal: to die. And unfortunately for the entire planet, his nature as both an immortal ghost wizard and world's biggest drama queen means he could only go out in the biggest way possible, and cause a whole ton of collateral damage when doing so.

I was going to say that Fandaniel is a very complicated character, but the interesting part about him is that... he actually kind of isn't? He's A LOT of character, but every individual part of him is very straightforward. He was never really hiding anything about himself at any point, but not all of him was relevant at any given point, including to himself.

[Lyth]

...

These are all interesting points.

I'm particularly curious about what they're going to do for the 6.4 and 6.5 trials. Two of the four fiends ended up being simply boss battles instead of full trials. It's hard to see why they would want to do that, unless they have a Geryon fight lined up. But two of the four fiends are also sealed up in Memoria, which perhaps makes that less likely. There's also a question of timing. The dramatic point to unveil Golbez's grand plan would be 6.5, so what do we do until then?

As much as I'd like to know about Koshu, I don't know if that would be the focus of an expansion. Thancred is bound to make an entrance whenever he returns, and I expect that he'll come to us rather than the reverse.

[Kesey]

These are all interesting points.

I'm particularly curious about what they're going to do for the 6.4 and 6.5 trials. Two of the four fiends ended up being simply boss battles instead of full trials. It's hard to see why they would want to do that, unless they have a Geryon fight lined up. But two of the four fiends are also sealed up in Memoria, which perhaps makes that less likely. There's also a question of timing. The dramatic point to unveil Golbez's grand plan would be 6.5, so what do we do until then?

I'm secretly hoping that we'd get a trial with all 4 fiends at once (In ff4 Golbez revives them for one last stand off together), doing wierd mechanics that would come from their old mechanics happening together at the same time, but the story isn't really giving us that evidence. 2 fiends are supposedly dead because they died on the source and 2 are crystals.

One of those trails is probably a fight with Golbez, but we'd still have to fill 2 dungeons and 1 other trial with something more before we get there. But he made this whole speech about going it alone. So I guess he could have subordinates for us who aren't considered his equal in the way the fiends are?

[Kesey]

...except that was exactly what Fandaniel was going for. He even reminded us of it right before he took Zodiark.

Fandaniel was a fantastic character with a surprising amount of facets and my favorite Ascian by a long ways because of it, but at the end of his life, Fandaniel-as-Amon had an extremely simple goal: to die. And unfortunately for the entire planet, his nature as both an immortal ghost wizard and world's biggest drama queen means he could only go out in the biggest way possible, and cause a whole ton of collateral damage when doing so.

I was going to say that Fandaniel is a very complicated character, but the interesting part about him is that... he actually kind of isn't? He's A LOT of character, but every individual part of him is very straightforward. He was never really hiding anything about himself at any point, but not all of him was relevant at any given point, including to himself.

Yes, what I meant in my original post is saying this phrase is a misdirect because it means literally what they said and something more. And we clearly have no idea what the something more of Golbez's plan could be.

[Iscah]

One of those trails is probably a fight with Golbez, but we'd still have to fill 2 dungeons and 1 other trial with something more before we get there.

Only if you assume he's the 6.5 trial. If he's in 6.4, there's only one dungeon along the way.

(For that matter, hypothetically they could go completely unpredictable and throw us the trial first, or put the dungeon in Pandæmonium, or something wild like that. Probably not, but they could.)