I had thought we might reach some level of mutual understanding and agreement, as I had thought our views are not actually very different.
As I see it, the "sense of exceptionalism" as you call it, only exists as an element of the specific story and character (Shepard and Shepard's story). Without the story, and without the character of the story (Shepard), there is no "sense of exceptionalism". The "sense of exceptionalism" of ME3 is an aspect of the character Shepard that exists only as a part of Shepard's story. Though a similar sense could be developed as part of a different story, a different character set in different story would still be needed.
Perhaps you would enjoy a game featuring a "sense of exceptionalism" devoid of any character featuring that characteristic. I personally wouldn't know how to interact with an abstract characteristic in place of an actual character set in an actual story.
Sorry we couldn't achieve understanding.
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At this point, every game conveys a story as every character through game actions creates a sequence of events that must be called a story.
And consequently, there is no storyless game.
Each stage in Pacman developps a story as the player takes actions through the character.
The issue with that is that players seem to distinguish between pacman type of game and ME3 type of games, attributing a story to the latter, not to the former.
Certain games with open and open ended world like M&B are also considered as providing no story. Yet every character crafts one's story through the player's inputs.
I have no issue with taking the route of the player's inputs and characters'actions shaping a story but a distinction between constrained (scripted) story and open story still is.
Once this distinction is made clear, player's concerns about ME3 were more about the scripted story. A game like M&B provides no plot holes, the story is as the sequences of the player's actions impose.
And that the lack of exceptionalism feeling comes from the scripted story, not so much from the action sequences Shepard is led to take.
As to the last point, most interesting, linked to the first point: a game can deliver a sense of exceptionalism by leading the player through the resolution of exceptional situations. The character would turn into an exceptional character by the results of his actions in the gameworld, without them being part forcefully of a scripted narrative. ME3 uses some mechanics to support this, included a scripted story but it does not have to go through a scripted story.
And yes, I would like to play a game in which at the start and without any script, the character has opportunities to grow exceptional. That could even be a RPG.