It's not quite player rolls or dm rolls - it's attacker rolls or defender rolls. The example in the 3e UA is player rolls, but it's extensible.
We are talking about miss for half damage, I agree. I use the 3e UA rules to convert saves into attacks vs defences. I cast a fireball at a creature, it could be a PC or an NPC. There is no change to the fiction input. There is no change to the fiction output. The only difference is that now the die leaves the hand of the attacker rather than the defender. I roll poorly and miss their defence. They take half damage. They have taken damage on a miss, resulting purely from the administrative re-organising of who rolls.
I am playing standard 3.5. I use a sword to attack a human NPC with a Dex of 10 who is wearing Full Plate. Their Touch AC is 10. Their AC is 18. I roll between 10 and 18. I have hit their touch AC (so in fiction, I have struck them, this might be narrated with the ringing of steel on steel or similar) but I have missed their full AC (so mechanically and in fiction, I have not impaired them). By the plain meaning of the word and the fiction, I have hit them, just not in a way that impairs them. In the mechanics, I have missed them.
I'm not saying that damage on a miss is a good idea, or that it should be in any particular game. I fully accept that rolling the die may be preferable for many reasons and you may prefer the current split of defences.
The point was that much like the difference between roll-under and roll-over mechanics (or descending or ascending AC), damage on a miss is (given the correct setup of probabilities) identical in the fictional input and the mechanical and fictional outputs. At least in 3/5e you can convert AC to a save or saves to AC-like defences with no change to the game, it's just that some people, for whatever reason, prefer a split
This would seem to setup a conflict in the manifesto presented earlier.
That is, that manifesto claimed that mechanics are never more important than what is in the world itself.
But giving a mechanic a label like "miss" (or "hit" or various other things)
is in the mechanics, not in the world. It's purely the label we assigned to a mechanic we're using to simplify the world enough to be workable. The world is whatever it is; the
mechanics assign labels. Surely, then, we should
ignore the fact that the label is "miss" or "hit" if the mechanics are always 100% secondary to the world.
Rolling an attack roll isn't a physical thing in the world. "Hitting" or "Missing" on an attack roll
also isn't a physical thing in the world. Hence, the label assigned to the mechanic shouldn't be relevant to our determination. Only what makes sense within the world should be relevant.
But, as shown in both this thread and many, many,
many other threads, that's entirely the opposite of true. Instead,
the fact that the mechanic is called a "miss" or a "hit" is what is primary. The world
needs to reflect the label attached to the mechanic. If it fails to reflect the label attached to the mechanic, then the world is wrong and the mechanical label is right.
How can that be? How can we have this situation where a dozen-ish folks in this thread are vociferously in favor of "the world is ALWAYS primary, mechanics are ALWAYS an abstraction and thus always at least somewhat wrong", and yet so many of those exact same people are also vociferously opposed to this, and instead expect--even
demand--that the world MUST reflect what the mechanics said, not the other way around?
Edit: Totally unrelated to the thread, but did anyone else have an issue for about half an hour there where you just couldn't open 99% of threads? I tried on every device, both logged in and not logged in, and just couldn't open
almost all threads. The only ones I
could open were pretty old, but even then some of those didn't work.