You’re 100% correct that no species is perfect, Venat said the same, the point being to not seek perfection as it will never be found, but instead to try to improve where you can. The point of the Sundering wasn’t to give rise to Venats ideal people, it was to prevent the Ancients from condemning all life to a path that would lead to despair.
Remember her words from when she Sundered the world
The point isn’t to create a “better” living being, but to ensure that the temptation to rely on a deity for answers and solutions could not come to pass. If her only interest was to create the Sundered, then it would be counterproductive to alert the Convocation that you disagree with them as you potentially just give your enemy more time to act. No, she genuinely wanted the Ancients to live on whole, her attempts at reaching out to others and pleading with them to change proves that.From that temptation, I sunder us!
But they obviously didn’t a thus summoned Zodiark. Tragically, Zodiark was made for the salvation of the star, his heart was Elidibus, He was by all accounts a deity that would be solely dedicated to the Ancients. But, in creating Him, the Ancients in essence assured their own doom when inevitably Zodiark would falter and suffering would again turn to Etheirys. They would be unable to come up with an answer, as there only answer, Zodiark, had failed. Thus, to prevent that future, life must be “sundered” from that temptation, one Venat never judged.
On the dragons: In the quests in Ultima Thule, you find out that Midgardsormr was widely mocked for his decision to flee and that is why he was the only one t make the journey. Midgardsormr had the answer, for sure, but his answer brought him to Hydaelyn/Venat and away from the Dragonstar. His answer and hers were in synch. And the dragons left behind, who yes wanted to live before, experienced the horrors of a war that led to their young being killed and corrupted. Now, they have no interest in living, preferring to become as stones.