A thing that I wish they could explore is "synced monsters" everywhere. I get it, back in the days, it was normal to have areas with a certain level.
But, this makes things like Cactuar around Uldah : Level 1-3, just passing next it make him melt, while cactuar in tulliyolal are booster level 90+ monster. But in the end, they are both part of the same species.
This could also allow them to bring back some of the older classic monsters that we don't see much anymore but that are so classic FF that we'll always be happy to fight some.

So yeah, every region should have "synced monster".

And on every expansion, they should at least release one dungeon in the older areas, do a questline "similar to Hildibran" that goes around old areas, etc.

I told earlier today to a guild member "I'm teleporting to Ala Ghiri" and he was like "where the fuck is that" and then when he realised it's SB content he was like "My god I haven't teleported there for at least 3 years".

It's a bit sad, those area exists, and we still can have things to do there. They probably could even update the fate system with bicolars gems there too.

I mean, it's not because we cleared the main story there that we should let those area die. Side quests doesn't have to be borring as fuck. Hildibran-like quest are engaging and fun. Maybe they should spend less time when developping a new expansion on meaningless "yellow quest" that many people doesnt do or even bother to read because it's random stuff like "Yeah so, I know it's the end of the world, but, could you please move that crate over there? Oh and my sister lost her panties in the river, can you get them back? Oh, and I want a steak for dinner, can you go kill that monster and bring me back it's meat? You surely don't have anything more urgent to do anyway. You're just a low grade adventurer right, not THE adventurer that is actually saving the universe right ?"