Personally, I think I think what
@clearstream is driving towards may be more about the guiding questions that lead to the design. Those narrative and indie game influences he identifies are not positioned as they are in their source materials; the driving question of the design is not "who has the authority to say what happens next?" That's sidestepped or often explicitly still assigned to the GM, and it isn't boiled down to that question, instead still referencing all those other roles the GM has. You're still playing the opposition, making choices for them that are separate from the PC's actions, and still creating a setting, but additional rules exist to influence what the GM should create, or to limit the opposition's palette of actions.
The question is more "does the GM need unlimited authority over the rules, the setting and the opposition?" and having decided the answer is no, the next question becomes "what is the effect of setting different limitations on that authority?" I don't think it's really worth getting caught up in the mechanism underlying that limitation; quickly you get to the constitution of a game itself and you start having to justify the rules for how a knight moves, which is a separate, not particularly germane discussion.
If you take it as a given that if you tell the GM they must, for example, respect something like a death flag from a player, and can only make choices for the opposition that will result in the player's death when it's indicated, then you end up in a "trad, but" space, which I think is what's being called for, with the design question ultimately being "but what, and why?"