EDIT: I had suspected this was bait and well it seems the undying Titanmen/Raging Stallion is at it again. Oh well I'll leave the post here because it appears some have liked it, so I suppose it's not entirely useless.
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There is ample warning in the cutscene itself that a jump scare could happen. The cutscene literally sets up a horror movie vibe. Sure it made me jump the first time I saw it too but it was not out of place at all. It wasn't unexpected that there was a jumpscare, it was more that you had no way to know exactly when it would happen.
You would have to be not paying attention to the story for this sort of thing to be unexpected.
I don't understand why you were expecting a lighter tone. We were liberating a nation who were being severely oppressed as a result of a war that happened in living memory and all this was known at the end of HW, and long before Stormblood you have warning that this game often doesn't hold back on horrible details.
In the msq alone there are cutscenes of a cute lalafell being assassinated through poison that clearly causes her fear and agony, a distraught highlander losing his arm in a fight, and an elezen getting a hole in his torso from a selfless sacrifice that even caused internal bleeding to seep from his mouth. And this isn't even anywhere close to being the full list of disturbing scenes or plot points. After seeing these scenes, how can a person be surprised that the game shows some of the disturbing things that happen in war?
Good god the first dungeon has human trafficking. Anyone who noticed that would know right away this game has some dark themes.
Well you were supposed to be unprepared for it. That scene is iconic hugely in part to how it took almost everyone by surprise.
Sure a trigger warning may help you but I think you perhaps forget that triggers are a deeply personal thing. I have anxiety and none of the things that triggered you triggered me. There are other scenes that deeply upset me to the point that I had to take a break but I understand it's because of the unique circumstances of this thing called "my life" and not because SE failed to do something. If SE were to put trigger warnings on anything that could possibly be upsetting to those with anxiety and/or trauma there would be so many that the warning would just lose its meaning.
We already have warnings from age rating, game genre, genre of storytelling, and how the story of the game progressively gets more dark the longer you play, to serve as warnings to those who may be sensitive to certain types of subjects.
I'm not against SE putting in trigger warnings, as long as they're not there by default (because spoilers) but I don't think it's fair to say that all these triggering scenes don't come with some manner of warning already.