There are some things I dont think everyone is really grasping some core concepts. We're pointing out that the Sundering may have been unintentional and that's fair, if I cut my brother in half I wouldn't expect all my nieces to suddenly get split in half as well. There's also the very real possibility Hydaelyn did know it would happen, but as she was a carbon copy Light variant of Zodiark believed she could keep everything stable but was too weak after the fight.

But there are some more important aspects of Hydaelyn that must be taken into account. The first being, Hydaelyn is not a person. She's a Primal. And that's a very important distinction, Primals are simulacrum. They are essentially super advanced magical A.I. They don't have any true will of their own, the closest any Primal has ever come to have done so was Ramuh and that was only in-so-far as he was summoned using the image of a wise sage thus he's capable of understanding that Tempering is antithetical to the protection of the Twelveswood. Or Alexander, summoned to be a literal fortress sized super computer oriented towards preservation, thus capable of understanding his existence is antithetical to the preservation of the Star.

Hydaelyn was summoned under these instructions:
- Resist Zodiark's Tyranny
- Preserve the new developing life

And it's not a stretch she was also instructed to NOT be like Zodiark and be a tyrant.

They pretty much just coded a program and hoped it would work. And we also have to remember Hydaelyn is the SECOND Primal. All of Hyaelyn's mistakes and mishaps aren't the result of her being evil, or even from her being a person and thus fallible. It's the result of her essentially being the second magical robot ever and thus not being incredibly well refined. Arguments about good and evil are irrelevant because Zodiark and Hydaelyn are basically just flawed AI.

What this does bring up is the conversation of what is evil in FFXIV? Ran'jit? Zenos? The Three Ascians of the Source were Tempered but we can't be sure that recruited Ascians such as Nabriales or Igeyorm were so are they evil? Is the evil in FFXIV the herd mentality of Empires in the form of the Garleans and Allagans following the order of their leaders to kill thousands without question? It's a theme I don't think many people have picked up on in FFXIV, "evil" isn't that simple.