More speculations from my side:
  • We'll finally see the rest of the named Ascians who might be of importance in 6.0 or others might be in the Pandaemonium raid series just like Lohgrif and Mithron were in the Eden raid series
  • Since Endwalker involves the "end" of the world it might not just be Source that is affected but other shards as well (maybe we'll use the Azem crystal again and it might summon the current strongest warrior of lights from their respective shard, maybe the other shards of the Azem like Ardbert?)