Ok, can you tell me the narrative relevance of Thavnair or any of the characters there? What purpose did they serve in terms of the story? Could you have replaced them with virtually anyone else and gotten the same outcome? How about the moon? Was exploring the Loporrits base really necessary to the story at all? No it really wasn't.
But do you want to know what the worst part of this expansion was? Fandaniel and no, it wasn't because he was an over the top cliche villain. The reason why Fandaniel is the worst part of the expansion is because they ruined his character. He never wanted to be Fandaniel and clung to his past life as Amon with his motivation to be a loyal servant to Xande and bring about the ruin of the world so that they could all share in the despair like his king had. The problem with this, however, was Hermes and Meteion. After Hermes finished listening to Meteion's report, he was just as prepared to condemn humanity as his sundered counterpart was and it belittled Amon as a character. His motivation was cheapened because it was something that he'd already done, so the motivation didn't feel like his own anymore but rather an extension of his past life as Hermes. To add insult to injury, they throw in Meteion as the true final boss of everything.
This is literally the FF9 Kuja into Necron story all over again. A fleshed out villain being tossed side for a 2 dimensional entity bent on total annihilation simply because "Death is the only answer". That's not good storytelling, and for a decade long story like FFXIV has, I expect better than a rehash of a previous FF title's end game.