Shadowbringers had the background to build for the story, albiet they did ride a lot into the setting they picked the villian they made of Emet Selch was a hard one to match with any others. Heavensward did set a good notion, and even used death to an effective measure as we have seen before. The issue is they never continued having the weight of death sitting around again. Perhaps it is because they did not want to have too dark a tone, or as someone else eluded to the notion of our precious Hydaelyn being less than a beacon of justice and right.
Ultimate Thule had a lot of potential to introduce us into the threat they so made. It was a good method to have the illusions of civilizations and planets lost to introduce the threat with giving how it could manifest outside of a few quests and a single duty roulette. It had potential to be a great showing that could of been used through out the post story to that conclusion with a battle with. But guess it had to be slammed in and done so we could not be bothered on that.
