I think what you call 'meta' is what I call 'process'. I don't draw a distinction between 'game' and 'meta game', that is a very 'Gygaxian' classic early RPG sort of position (though it has certainly hung in there amongst a crowd which includes a lot of people here).
It's not Gygaxian at all -- I don't care about "metagaming" in the context of character/player separation. I'm using meta in the context of the game about the game -- ie, rules not on what you do in the game but instead on how you're supposed to use the rules of the game. It sits above the mechanics. Again, I point to the clearly defined principles of play that PbtA games provide. "Be a fan of the PCs" is not a rule -- there's no application of this rule that can be seen. Instead, it's guidance on how you're supposed to use the rules that are provided, ie I should use rules from a position of wanting to see how the PCs deal with the fiction and rooting for their success. This principle establishes a baseline for a game where the primary job of the GM is to make the PC's lives
worse. The GM doesn't really have much to do with a PC success -- that's up to the player. It's only in framing and failure that the GM has work, and that's uniformly to add adversity and consequence. This principle sets the tone -- that while the GM is heaping on adversity, they're supposed to remember that they should be rooting for the PCs to succeed, or to showcase their grit and mettle. This prevents PbtA game from spiraling into GM vs player. As such, it's a meta rule because it's never realized at the table but instead only in how the GM applies the mechanics and the choices the GM makes in doing so.
Thus I don't see the difference as so much one of principles of play and such as it is a straightforward difference in tool sets. DW does not have a combat section in its rules. It doesn't talk about resolving fights and what happens in fights, except incidentally as it may be an example of 'dangerous situations'. It does provide 3 moves, 2 of which are totally combat specific (defend can be applied in a few other situations). So it COVERS combat, given that it is a significant class of activities, but "resolving combat" is not one of the processes of DW. Advancing a narrative, including combat narratives, IS. Note again that there are no distinctions in its rules process for combat/social/exploring, etc. They are all moves. The only difference is which move might be relevant in a given situation. This is entirely different from 5e where there are things "the rules don't cover" or where a distinct 'check' system is used which is different from combat. The 5e combat rules are specifically discussed as providing resolution of what happens when you swing a sword, etc. DW simply says "describe what you do" and then some move or other will be mapped onto that. Nobody in DW would say "I go hack and slash on the orc!" This is not because of 'principles', it is because that isn't the PROCESS OF PLAY! You say "I want to hurt the orc with my sword" and yes, that maps pretty directly onto Hack and Slash, but that is only one case. You could easily decide that retreating from the orc uses Defy Danger, etc. In 5e you would specifically call out rules you are using, "I'm swinging my sword at the orc." or "I disengage from the Orc." These would invoke specific other rules, like maybe OAs, triggering the use of class abilities, etc. Note how this all happens in a turn order, which simulates a strict advancement of time. DW has no concept of time. The fiction advances, maybe a little bit, maybe a lot, it just depends on what moves are made. It may well be that only one PC will even take moves in a combat in DW, and there is no rule about who gets to do what, when. The narrative and logic of DM moves is entirely in charge of that.
The focus on how the rulesets prioritize play details is a red herring. You've tried to use this to say that the difference between DW and 5e is that DW rules advance a narrative while 5e rules... I'm not sure what you mean to contest here but the implication is that 5e rules don't. This is not at all true -- both rulesets advance the narrative. There's a distinct difference in the tech used, and how that tech operates, sure, but just looking at the tech doesn't really make much difference at the end of the day. Yes, if I'm playing 5e I have more detailed rules for resolving a combat than I do in DW, but they also both advance the narrative, so they don't do different things. HOW those rules are used, though, is the important distinction, and this is the meta level of principles I'm talking about.
5e is generally used in a way that isn't conducive to "play to find out" principles. This is because D&D traditionally is based on the principles of the GM scripting at least a story outline and then presenting this in play for the players to explore. This is different from other games, like DW, where there's a minimum of GM prep and the fiction is intended to be discovered through the play. But, the actual mechanics of DW don't really do this -- you can run DW using the D&D style of approach. Like trying to run 5e purely on a narrative approach, the results are not ideal because there's a bit of a mismatch between the tech and the principles. Games like DW have tech that's designed in concert with the principles of play, and made to match, so that when you use the game tech according to the intended principles of play (the meta), the results are bang-on. 5e, on the other hand, and 4e before it, don't provide a clear statement of principles of play and instead let the individual tables come up with how that would work. 5e can be used narratively, but it's not a great fit because the tech is borrowed from D&D tradition and is aimed more at specific task resolution and fortune at the end style play which doesn't well align to narrative goals. Still, the tech can function pretty well in a large number of situations, just not as robustly as a game designed to do so. Which is why I'm arguing about the earlier statement that 5e doesn't have tech to resolve the shed toy example -- it does, if you're using an appropriate principle.
And, fundamentally, a lot of what's confused in this discussions are the principles of play. This is the source of much of the arguments on playing 5e alone, much less in comparison with other games. The fact that 5e doesn't clearly state principles of play and leaves those open to tables means that the traditional principles of D&D play are confused with what 5e presents. You don't have to do a GM lead story in 5e, for example, that's just the traditional way of doing it.
Now, maybe you see some principles being in charge, but I think that example of "playing DW like 5e" is MECHANICALLY FLAWED, and I could point out specific places where the rules of DW were broken. If its rules were followed, the game would PERFORCE be a story game, it could not be otherwise (Admittedly, the principles exist for a reason, I'm not denigrating them, but their purpose is more to make the game work WELL and break people of their 'Gygaxian' habits vs being what makes the game itself mechanically work).
No, I violently disagree that if you just use the rules and not the principles of DW that it would perforce be a story game. Recall that the fundamental principle of DW is 'say yes or roll dice' and that this is what functionally enables the story game, or narrative, play style -- that the GM cannot refuse a valid action declaration based on hidden backstory but must instead either accept it or challenge it with the tech. D&D, on the other hand, uses a clear "the GM decides" principle at the core of play -- ie, the GM can say no because they've determined, for whatever reason, that the given action fails. If you swap the DW principle of "say yes or roll the dice" for "GM decides", then the tech still functions, but the outcome is no longer a storygame. A player can attempt a move, say spew apocrypha, and the GM can just deny an outcome, even with a roll, because that's the principle at play. Here, the GM can run DW or AW or whatever using the GM decides mechanic and have players explore the GM's notes, so to speak, and it will work. Not well, and not at all what an experienced player would necessarily recognize as DW, but it will work and it will not be a storygame. You have to have the principles of play -- those rules not about what happens with dice or moves or whatever, but about how to use those rules -- the rules about the rules. Without these, there's nothing that prevents DW from running like badly organized trad D&D game.
I think it is less accidental than you do, much less. We agree, it CAN be read either way. As I said, I think this was kind of necessary, the story game advocates don't seem to have had absolute sway, or probably even the most say in what got included and the exact wording. Pity.
I don't think there were any storygame advocates on the 4e team, at least in the sense you seem to be taking it. Because that would imply that they had enough pull to add a storygame mechanic but not enough pull to actually explain how it works. If explaining the mechanic would give away the game, so to speak, and be a bad thing, why on earth was it allowed to be added? Because, I think, it's not meant as a storygame mechanic, it's just fluid enough that if you apply storygame principles it functions as that as well. I look at it as an attempt to iterate on complex skill checks from 3.x. The initial presentation, with the flawed math and poor explanation looks exactly like this. I think that it was recognized that it could work as a story game tool by the time Essentials rolled out, so there was some caveating to allow for that approach, but the core of the mechanic is still very close to how it was initially, just with better math and a few additional bells and whistles.
Anyway, you can come play HoML sometime and see how you would take those principles and design elements of 4e and go all the way with it
I have little to no interest in your 4e heartbreaker, but thank you for the offer.