Xelphatol is Ixali territory, and it would seem Coerthas Eastern Highlands has fallen to them, given the gate just north of Natalan. I'm fairly certain that will be an entrance to Xelphatol eventually, Gridania doesn't really have a clear path towards Xelphatol... North Shroud might, but that's really unclear IMO, just like a path to O'Ghomoro, early concept maps might indicate a route through the Logging Grounds, but the gate in Coerthas is very obvious IMO... I don't think Coerthas Eastern Highlands (which I suspect we'd skip over just like Central Lowlands) is too far west honestly... If you look at the maps like that, there is no way Thanalan and the Shroud connect...
I would hope 4.0 actually end up being a Grand Company expansion, with Gyn Abania as an endgame "Alliance v Garlemald" area, and O'Ghomoro, Paglth'an and Xelphatol as "Company v Beast Tribe" areas. That would provide some nice potential for new Grand Company content to flesh out new Ranks (Campaign~!), and it would also avoid the issue of locking everything behind the previous story... Gyn Abania might well be locked behind the story, but why would O'Ghomoro/Paglth'an/Xelphatol? Much better way to deliver new content IMO, hope SE doesn't go the same route as Heavensward (where they should have given us a new mid-level Coerthas zone for new Jobs, rather than locking literally everything behind 2.55...) and lock everything behind 3.55 and just provide a skip method for the lazy...