I wasn't even thinking about that part when I made the statement. However, I don't think that that is the best example. All of the followers have unique content specific to them because they are set characters, but they can't do that for the Inquisitor, just as they can't have Cole read him as he does with the other followers. You can't account for that sort of RP variation when it comes to things like personal fears. In that case, I vastly prefer the DAI method of a generic statement from Nightmare, leaving the rest to headcanon, rather than saddling me with thoughts or feelings that might be a gross misrepresentation of my character.
However, you overlook the fact that we do get to emote about it in the post-Fade dialogue with Dorian where he specifically asks you how you're doing; you have several (more then the typical three) responses. There is also a dialogue with Varric specific to the big choice. So it's not all left up to headcanon.
If i close my eyes i can hear the demon taunting my Amell about helping a blood mage escape, or my Cousland about leaving his parents to die, my Tabris about accepting Vaughn money/not saving Shianni in time ecc ecc. Those things would actualy shake my character because i he, and me both, lived them. They didn't do this in Origins, i think, because even back then it would have come out as forced, just as it happened in Inquisition IMHO.
Fear in a character, as you said, is a touchy subject, and if they really wanted to implent it in the game they could/should have sneaked here and there some questions about the character's fears and motivations (Leliana/Varric asking if there is a creature the character considers fearful, a discussion about regrets with Solas, Vivienne/Dorian/Solas talking to a mage about Tranquility and if they fear it, fear of losing the LI ecc ecc). As it is, the demon of envy taunts my character about what The Inquisition would become if he got possessed, which just feels impersonal, and the demon of fear completely overlooks him.
Sure, i can go talk with Varric and Dorian and explain how he felt and, as i said, i can headcanon everything....... but i still can't help but feel that my Inquisitor wasn't even touched by the things he experienced because everything felt so impersonal. Most of all the Stroud/Hawke choice, which, again, is hard for the player and not really for the character (Especially since, by that point, the Inquisitor has sent Makeronlyknows how many people to die through War Table missions)
Another choice like that (player vs character) is Leliana's "kill the traitor or don't"(at the very beginning of the game). I, the player, stopped her because i didn't like seeing Leliana like that, but why would my character, someone who just met her and who just got back from the Hinterlands after killing something like 50 people, object about her giving a quick death to someone who sent Inquisition's people to die. That's just Merrill Act 1 level of naivety