I also think Sharlayan is going to play a big role in 6.0. Their nation seems to have many similarities to Amaurot and the Ancients, like the Greek terms mentioned. They also share many themes, both being isolationist nations made up of academics, debates being a pillar of their society, etc. Louisoix's departure to Eorzea is mirrored by Azem's departure from the Convcation (hell, maybe he was inspired by some remnants of Azem's writings). And when you're in Amaurot, I'm pretty sure the WoD could potentially quote Louisox when talking to the people arguing about whether Amaourot should help the other places fighting the Sound or stay isolationist. Maybe their nation was founded on some Ancient ruins but then you have to wonder why the Ascians would allow them to stay. Or maybe they've been collecting and hoarding Ancient info and lore; I think there's something like there's some knowledge that only people born on Old Sharlayan has access to, and they don't allow it to be shared with outsider academics.

And then there's the things like the Ancient dungeons having jazz music and Gubal Library being distorted jazz... The nautilus being on the Sharlayan flag and a big nautilus statue at the top of Akademia Anyder... I don't think we're done with the Ancient story, and Sharlayan just has too many connections, thematic and otherwise, to just be world flavor. IMO anway.