Ovinomancer
No flips for you!
You're insistence that the GM has to narrate a fictional change requires this already, so I'm not sure what you mean here. If the orc takes damage insufficient to kill it, any fiction narrated about this event is meaningless -- it changes nothing. I am free to describe this damage as a grievous wound, which has not other effect other than color, or a narrow miss. I can, in fact, describe the loss of hitpoints in exactly the same way I could describe failure on an attack roll that has no impact on the cubes side. "Inconsequential" seems to be an apt description of your insistence that the GM must narrate a meaningless and arbitrary bit of fiction.Additionally consider under formalist and non-formalist views. Suppose you accept my contention that 5e rules require
F -> G
G -> G + G -> F
You (might) say that it is formally the case that some arrows are empty, because you interpret that no rules fill them. You add that such voids include triggers for fiction to cubes, and any consequences for cubes to fiction.
I can say that it is formally the case that those arrows are not empty because as a matter of fact there are rules throughout 5e that fill them, and a super-rule that requires and empowers DM to do so in their absence. I add that you draw an invalid distinction between impaired novement and reduced HP ongoing, because both are intended to matter. DM F > Play F.
As a non-formalist I say that we may both be right according to how we interpret the constituting rules. Where the constituting rules are in doubt, the game is in doubt. You could rightly ask why on Earth we would want the game to be in doubt!? I could mutter "rulings not rules" and point to popularity.
If we have a feeling that Play F > DM F is best, then empowering DM sufficiently to do as 5e as written requires might defeat the form of play we have chosen to value. There needn't be any conflict, however, if DM uses their powers according to the best way.
So to you, narrates means say something empty of meaning? Inconsequential?
The consequentiality of the "narration" here is that the GM acknowledges a change on the cubes side that has no change on the fiction side. Insisting that a change on the fiction side is mandated by the basic play loop is what generates situations empty of meaning here.