This truly might be a case of Occam's Razor. With that statement many of us are pondering where 6.0 will go but the way it is set up and has been for the past two expansions it is most likely Islabard. Yoshi P. might have been misdirecting it due to the statement similar to Benidect Cumberbatch character in Star Trek into Darkness being said not to be Khan when in fact he was or Christopher Waltz not playing Blofeld in Specter when once again he was. The story has been pushing Islabard hard for two expansions now especially with that final scene in 5.3. Also while we will have to wait for 5.4 to get a better picture, past x.3 patches did show a little bit on where the next expansion would be. 2.3 began to show the Ishgardian plotlines develop and 3.3 did the same for Ala Mhigo, the only one that did not if I recall was 4.3 as the location for ShB was kept under heavy wraps up to the third fan fest.

While they did do the curveball away from Islabard last expansion, to set up the long awaited Ascian expansion and show just how high the stakes are with the other shards, I do not think they will do it two expansions in a row, especially with locations already somewhat developed and made. I feel Yoshi P. wants to wrap up as many season 1 story lines as possible and that most likely includes the empire as well as Hydalyn/Zodiark, allowing the next storylines to be less tied down and explore new territory. Also I feel at this point they have just done about all they can with the Garlean Empire, to keep them around as antagonists for another full expansion will just get a tad repetitive and stale.

That being said I seriously hope we do not have to have another expansion with Zenos as the main antagonist, that right there I feel will especially get old and tiresome especially after the more complex and ironically human antagonists of ShB like Emet-Selch and Elidibus.