Fun fact, Endwalker is only barely above Shadowbringers in named character bodycount. Like, it has one more death.
I think both Shadowbringers and Endwalker get by on the 'piles of anonymous bodies' factor; sometimes, throngs of nameless corpses set a tone of 'dark and serious and full of death' that the rest of the game just doesn't have to deliver on and people will still act like it did. I always think of Dragon Age Origins: people act like that game is a dark and serious game full of death, but the actually meaningful bodycount is so low that depending on your character origin and choices it might well be at one. Meanwhile, Dawntrail basically has the inverse; it actually is willing to kill characters. But it instead kills specific characters in one-off incidents, it doesn't pile on the bodies; and when it does, it doesn't discuss them. (The Solution Nine attack is the bloodiest it gets, but the focus afterwards is on supporting the survivors.) As a result people just act like it's bloodless and light, when it really isn't.
There's an amount of people that will only ever respond to the visceral; that the stakes are only dire and bloody if they look dire and bloody, damn all evidence otherwise.
All that said, I do think there's an element of truth in it not 'feeling right' if the Scions died in, say, Dawntrail, even if Dawntrail's meaningful bodycount was actually quite high. Because Dawntrail's deaths were meaningful; they affect the people and world around them. Gulool Ja Ja doesn't die for raw shock value, his death fundamentally changes the character relationships between Zoraal Ja, Wuk Lamat, Koana, and the city of Tuliyollal. In that context, one of the Scions dying would feel wrong, not because the space around them isn't dangerous, but because this isn't their story. Their death wouldn't affect anyone around them, because most of this continent doesn't know or care what a Thancred is; his death would be a meaningless speedbump, when he deserves more.