My take on the Venat/Emet-Selch thing is this:

Emet-Selch is a pitiable villain (after he gets blasted by Kairos), and a good man before. But once he gets to the point that he's willing to destroy thirteen worlds to bring back the old world, he can't be called sympathetic. It's even a bit funny to me that he gets upset at the idea that people would fight against the Ascians and claims that them trying to claim the worlds for themselves is arrogant, even while he claims the world for himself and his people just because they came first. That said, I imagine at least part of that is the result of being brainwashed by Zodiark, as he's a lot more lucid on revival, even if he's still a little salty at Venat.

Venat on the other hand is a little... complicated. I think it's the result of telling a time travel story, which I've admittedly rarely been a fan of. I feel that Venat has very good intentions for what she does, much like Emet-Selch. She is the only one who is aware of Meteion's talk about life on other planets eventually choosing death and sees the people offering their lives to Zodiark as the same thing. Understandably, she's disturbed by that, so she sunders the world in order to give life a chance to survive. That said, Venat herself says that she's not sure the move was the right one, and the angle people brought up in this thread of "death of identity" is one I hadn't really considered. By the end of her actions, the only people that "survive" are herself, Emet-Selch, Elidibus, and Lahabrea, so it does feel a little tone-deaf calling her a hero, I suppose, even if I personally can understand why she did what she did. I also found her assumption that everyone could just go to a new planet kind of flawed since Meteion could just destroy that planet as well?

In the end, I feel like the Zodiark/Hydaelyn conflict had no one right answer. Zodiark was necessary to forestall the Final Days, Hydaelyn was necessary to defeat Meteion (since dynamis was apparently the only thing that could overcome her?). Both sides with the knowledge they had made the decisions they thought were right, even if the writing to get us to that point feels a little shaky. I suppose Venat never told anyone what she knew since she was afraid Hermes would pull some more nonsense?

Also, on the topic of Elidibus, I do feel like the Shadowbringers patches just kinda accelerated his role and changed his character a bit suddenly to the point he felt different from how I remembered him being, but I will say that I'm not disappointed with his actual fight. I rather like the idea that he is Zodiark and the Primal form he chooses is of a hero, because of course the people of Amaurot would see Zodiark as a hero given what he was summoned to do for Etheirys.