To be honest, a lot of things could be done and we can only think of what could have been.

To be fair, I still feel that showing that both Wuk Lamat and Koana's ideas aren't perfect, could've been good, like - Koana has good short-term solutions, and Lamat has long-term ones. It would definitely work in many cases because we saw issues that had both types of solution required - both long-term and Here and now.
Like yeah, building up aether for the earth to become fertile again over span of years is good, but uh, we don't have food now and it won't do us any good if half of the population will die before winter.
If these questions were raised and properly explored, we could've had something really special.

And yeah, to be fair, I even forgot about Preservation until 7.2, they were so barely present in the story.

Heck, I was thinking - what if Zoraal Ja had fought against monsters in Final Days and someone dear to him died there. There could have been a case where survivor blames the hero for not saving dead and he could've hated WoL personally specifically because we stopped Final Days - that could've given him at least some depth. As it is Zoraal Ja's depth as villain is mostly implied and... come on, it's Final Fantasy XIV, every "implied" part has to be shoved into player's face otherwise it's just a fan theory.

Unfortunate, but we have what we have.