For me, probably the most important "gap" between what Baker says, and discussion I often see about "narrative" RPGing, is that narrativist RPGing has relatively little to do with how the game is played on the player side. It's mostly about how things are done on the GM side: how scenes are framed, and how consequences are established.
Framing, in conjunction with PC build, is what creates the starting point rising conflict across a moral line; and consequences are how the pressure increases, and conflicts are resolved (or not).
Over the past few days I've been prompted to think a bit more about this.I think that how the player invests themselves in their character is pretty different. It's a much more active process than the equivalent that's sometimes the case in other games where the players can have a grand time sitting back and letting the game come to them, so to speak. That doesn't work so well in a game like Apocalypse World.
When I think of "sitting back and letting the game come to them" RPGing, the first thing I think of is AP-ish, quest giver-ish play. The second thing I think of is a type of dungeon-y play, but one that doesn't require a lot of planning and challenging operational play. And these two things can overlap.
Narrativist play, as characterised by Baker, isn't like either of those. There's no AP - nobody plans how things will turn out; things unfold "according to the authorship of the players".
There can be play that is demanding on the players that is not narrativist play. High intensity "beat the dungeon" or tactical combat play can be pretty demanding - players need to understand their resources suites and PC capabilities pretty well, and make sensible and sometimes inspired decisions on top of that.
An approach that expect the players to onboard a whole lot of setting and/or situation that is authored by the GM independently of the players and their PCs can also be pretty demanding. Like following a complex storyline in any other medium, the players have to learn their way around and through this fiction that is being presented to them.
It can sometimes be tricky to characterise the focus of narrativist play, and the manner in which it's demanding. It's not just the rising conflict, or the pressure. It's the moral line - the conflict arising out of passionate commitments that not only exist in the fiction, but that in the "meta" are what the GM keeps coming back to in framing and consequence. Or, at least, that's what I'm thinking at the moment.

