Il Mheg 1/2 of two mirrored zones?

[Nalien]

They never mentioned going to Azys Lla in the fanfests for Heavenward 4 years ago, so to answer the "If we're travelling to parts of Dalmasca, why isn't that also mentioned?"
Maybe its a story relevant secret?

They may not have mentioned it, but they definitely showed it... Pretty sure they mentioned it though, given I clearly remember them mentioning how they had to brush up on a lot of bioengineering terms when writing the lore for it...

It's in their Tour of the North trailer at the very least. I distinctly remember plenty of us speculating the Warring Triad coming off this shot.

As I recall, Heavensward was sold as; "Ishgard, Dravania, and the Sea of Clouds", with Azys Lla falling under the later. Stormblood was sold as; "Ala Mhigo and Far East", and that's all we got in terms of overworld zones. When Shadowbringers is being sold simply as "Norvandt on the First", why should we expect a secret Source zone? Best case, as with the Return to Ivalice raid series, YoRHa: Dark Apocalypse may take us to new regions on the Source, or some new Source area may be explored in the new version of Eureka.

Honestly, I'm not even sure if we'll be going back and forth between Source and First all that much... That kind of writing didn't work too well with Heavensward, and with Stormblood bringing in a lot of "Meanwhile... At the Legion of Doom" cutscenes, and the rise of Roleplay instances... I could see a lot of the Eorzean Alliance vs Garlemald story being covered in that method... For the Main Scenario at least, I suspect a fair few Job quests might actually involve the war on the Source and have us travelling back every 2 levels... Honestly I'd prefer all of 5.0s main story to be on the First, uninterrupted... I think it would have more dramatic effect for us to return to the Source after finishing our business there and then witness the effects of the war, rather than directly involving ourselves in the war or having constant cutaways to watch events unfold...