I hope it is clear that these two components of your post that I've outlined are specific GM principles that are specific to a particular play agenda. Which is good. Specific GMing principles to a specified and particular agenda is excellent.
But principle and agenda-wise, this is situating all three of play broadly, player decision-space, and GM responsibilities/authority to be centered around things that would be extraordinarily adverse in other forms of play. If play situates the GM as "reader of the room" when they're mediating action resolution, that can trivially Trojan Horse in a game theoretical model where social coersion (overt or covert, individual or collective) propels moments, sequences, or all of play. That might be deeply anathema to any number of play agendas. If play situates the GM as "responsible for the pulse of unfolding events," that might be deeply anathema to any number of play agendas; (i) those that want the pulse of unfolding events to emerge sans-GM orchestration or (ii) those that don't want a pulse of unfolding events to even enter into play at all (which necessitates that none of the participants are preoccupied by such a pulse!).
Its this kind of Trojan Horse (I'm not making an accusation here...these Trojan Horses get routinely deployed, smuggling in all manner of anchoring expectations that may or may not be examined), that becomes a problem when this kind of GM authority/responsibility in a void-fraught rules becomes married to player decision-spaces that are supposed to be simultaneously goal-directed as well as contingent upon reliability in all three of orientation to situation, attendant decision-space to be mulled, and action + resolution (which includes handles, leverage, currencies, consequence-space evaluation, and possibly even advancement scheme).
And to reiterate, this isn't about outcomes (though outcomes are important). This is about the moment-to-moment orientation to and processing of individual chunks of play. It is more about the input dynamics of this stuff and the cognitive scheme in which it situates players (which is where the "gameable space" thesis picks up).