Ala Mhigo, on Gyr Abania is a strong possibility of where the next expansion would take place. We try to liberate it and such. I don't see Garlemald being an accessible place anytime soon, though.
If sea explorations does happen and we go overseas, then maybe we can access Othard (where Doma and the Au Ra are) Ilsabard, and Thavnair (which Radz-at-Han is, if I recall.)
I'd like to see the missing areas of Eorzea though, like West Shroud and Coerthas' Lowlands, and the Eastern Highlands. Maybe Mor Dhona's missing southern part, too.

For jobs, Samurai is a strong candidate. Red Mage, Blue Mage and Dancer has been popular demand as well, I wouldn't be surprised if those are the upcoming jobs.