I'm starting to question why Hydaelyn, a being who was supposedly summoned in order to preserve the new lives on the star even possessed the ability to sunder the world in the first place.

It doesn't really seem to align with her purpose, unlike...say, Alexander's ability to travel through time, which fit with its intended purpose of creating an ideal world by enabling it to right past wrongs...or at least it would've had the thing not been simply too powerful to act without draining excessive amount of aether.

For that matter, I'm also questioning if Zodiark seemingly being tied to the resurgence of the Final Days might simply be because the Source simply isn't in a state to withstand the presence of an active primal as powerful as he is. Even fractured, he's liable to be several magnitudes stronger then Alexander, and while he doesn't seem to actually be free of the moon by the time 6.0 rolls around, perhaps simply being awake is enough to have grave side effects on the world.