With the Cristal Tower, Alexander and Omega raids becoming canon this expansion, I really think Ivalice raids, Secrets Weapons and Bozja contents will become it too.
Why ? Because we are freeing zones controlled by Garlemald, and without this moves, it would be impossible to get in their territories easily (Their presence in Gyr Abania and Othard was quite low by comparison) to reach Garlemald city and maybe face Zenos and build a new empire...or a republic with new allies.
At the end of Bozja 5.35,
Bwagi tells us that Fran and the resistance are progressing into taking back their land, Nabudis Necropolis, was it ?
And if we want to deal with Zenos and the empire once and for all, we need to go to Garlemald city.
Other note, with the 2 parts remaining for Bozja, I don't think Gabranth will be the last boss, but the other imperial guy (don't remember his name).
Gabranth seems to way important in the future because of his ideal to rebuild a great Garlemald Nation, imo.