In the broadest terms, I'm arguing that the basic structure of play from some related mediums can absolutely be applied to the TTRPG, which can differentiate itself from them without changing it. The unique features of an RPG can be expressed without changing the nature of mechanical engagement; I can use the same skills, decision making tools and get the same enjoyment from a game of Descent and a game of D&D, and they can still be meaningfully different activities, separated by other features. I've been saying consistently that I think that process of play you're describing is less fundamental than an unbounded play time and involved victory conditions. All this engagement with the fiction stuff can be offered into the actions/tools your game makes available, instead of a required part of action resolution.
You denied that negotiated imagination was fundamental to roleplaying.
So you can start to illustrate that claim by providing an example of your play in which nothing is being imagined.
I think
@chaochou's point is apposite here.
The boardgame Seven Wonders has "involved victory conditions" in the sense that there are multiple dimensions of play in which victory points can be accrued, and for relatively casual players the maths at any given moment (particularly at earlier stages of play) is not easily solvable to yield an obviously superior move. There's a contrast in this respect with, say, backgammon.
But if the victory condition is "light a signal fire on top of the mountain", achieving that victory consists precisely in everyone at the table agreeing that, in the fiction, some character or other has reached the top of the mountain and has lit a fire. Which is shared imagination. Given that, in a RPG, no participant has unilateral authority to stipulate either that the fiction does or does not contain such a state of affairs within it, it's
negotiated imagination.
On top of
@chaochou's point:
I've played RPGs which do not involve unbounded play time. Agon is an example, with a formal structure to support its lack of unbounded play time (both at the session level and the "campaign" level). I've not played My Life With Master but believe it might be the first - certainly an early - example of a RPG with that sort of formal structure.
As well as formal structures to constrain play time, I've played RPGs with an understanding among all the participants that play time is not unbounded, and as the GM I've used my authority over the fiction to frame matters towards and then into a climax at the appropriate time.
That's a mechanic that prompts the DM to change the adjectives used to describe the situation, but doesn't in any way change player decision making. On the other hand, if I can climb any wall at full speed, one handed while wielding a weapon at a DC 30 or whatever, then I can use that information to play differently than a character who can't do that, and differently than I could before I could do that.
I think in this particular post you are reiterating this point made by
@LostSoul a while ago now:
How the imagined content in the game changes in 4E as the characters gain levels isn't quite the same as it is in 3E. I am not going to pretend to have a good grasp of how this works in either system, but my gut says: in 4E the group defines the colour of their campaign as they play it; in 3E it's established when the campaign begins.
That's kind of confusing... let me see if I can clarify as I work this idea out for myself.
In 3E, climbing a hewn rock wall is DC 25. That doesn't change as the game is played (that is, as fiction is created, the game world is explored, and characters grow). Just because it's DC 120 to balance on a cloud doesn't mean that characters can't attempt it at 1st level; they'll just always fail. The relationship between colour and the reward system doesn't change over time: you know that, if you can score a DC 120 balance check, you can balance on clouds; a +1 to your Balance check brings you that much closer to success.
In 4E, I think the relationship between colour and the reward system changes: you don't know what it will mean, when you first start playing, to make a Hard Level 30 Acrobatics check. Which means that gaining levels doesn't have a defined relationship with what your PC can do in the fiction - just because your Acrobatics check has increased by 1, it doesn't mean you're that much closer to balancing on a cloud. I think the group needs to define that for themselves; as far as I can tell, this is supposed to arise organically through play, and go through major shifts as Paragon Paths and Epic Destinies enter the game.
But anyway: one key point that I take
@AbdulAlhazred to be making, or at least pointing toward, in his discussions of Dungeon World and 4e D&D, is this:
who gets to decide whether balancing on a cloud, or any other feat of heroics, will help the PC achieve the goal that the player has set for the PC?
I think
@Manbearcat is pointing toward something similar in his post upthread about the technical aspects of climbing, and genre logic.
At some tables, the answer is
the GM. Some RPG systems - eg 3E and 5e D&D - tend to reinforce this answer in their rulebooks and in their procedures of play.
At some tables, the answer is
the table - both player(s) and GM.Some RPG systems - eg BitD, DW, 4e D&D, Agon, Burning Wheel, MHRP - tend to reinforce this answer in their rulebooks and in their procedures of play.
It is possible to have a system with "objective" difficulties (like DC120 for balancing on a cloud) that otherwise fits in the second category of pointed to: Burning Wheel is an example. But in my experience that is aesthetic and has little relevance to player agency.
Suppose a player knows that,
should it be relevant to achieving their goal, their PC in this game is almost certain to be able to climb any wall at full speed, one handed while wielding a weapon. How does that give them agency? Who decides the relationship between performing such a feat, and achieving any goal?
That is all about who gets to decide the content of the fiction - in framing, and then how performing certain feats in the fiction will allow certain goals to be achieved. Negotiated imagination.