I don't agree with any of this at all, but I doubt just explaining why is going to suddenly convince anyone to change their mind...

The pacing is weird and I do agree that the Radz-at-Han aetheryte not being able to be attuned to is annoying for no reason. But I don't think this is some kind of crazy outlier when it comes to FFXIV. Even Shadowbringers, which was many people's favorite including my own, had that whole dumb section in Western Amh Araeng with the miners for the flimsiest excuse, Ran'jit showing up all the time and being super strong for no reason, and everything involving the mystel couple and Alphinaud in Eulmore. And that's to say nothing of the other two expansions and 2.x which are truly awful by comparison in this area.

I didn't even register a "darkness" theme, since by this time we know the story behind Zodiark and the Final Days pretty well. The whole story this time is payoff for the setup concerning these events in Shadowbringers, and a key aspect of any Final Fantasy storyline - we have to figure out the cause of the Final Days and the truth behind what really happened to get the world to where it is now, and we do. Zenos was pretty pointless and I really don't understand why the writers keep him around at all, so I do agree that he brought everything down here, just not for "story is too dark" reasons.

Everyone else has already mentioned that the Garleans act a lot like imperial citizens in real history. I also liked that our relationship with the empire ended this way - no need to have Stormblood part II where we have a massive world war to take them down, instead empires are naturally unstable and collapse under their own weight as soon as they have problems in the leadership. They're no longer a threat and this demonstrates it well while making way for the rest of the story.