My take is that GM-side creativity ahead of time, where one has a chance to think it over, refine it, augment it, write it down, or even chuck it if it ain't gonna work, is more likely to provide a better and more consistent game experience than if everything is made up on the fly.
This surely depends on the individual in question.
But anyway, here is a bit about prep from Apocalypse World (p 136):
A front is a set of linked threats. Threats are people, places and conditions that, because of where they are and what they’re doing, inevitably threaten the players’ characters - so a front is all of the individual threats that arise from a single given threatening situation.
Creating a front means making decisions about backstory and about NPC motivations. Real decisions, binding ones, that call for creativity, attention and care. You do it outside of play, between sessions, so that you have the time and space to think.
A front has some apparently mechanical components, but it’s fundamentally conceptual, not mechanical. The purpose of your prep is to give you interesting things to say. As MC you’re going to be playing your fronts, playing your threats, but that doesn’t mean anything mechanical. It means saying what they do. It means offering opportunities to the players to have their characters do interesting things, and it means responding in interesting ways to what the players have their characters do.
Accordingly, when you create a front, follow your own inspiration. Choose the things that are suggestive to you, that put you in mind of apocalyptica, romance, violence, gore, danger, trauma. Choose the things you’d just [freaking] kill to see well done on the big screen, and skip the things that don’t spark your interest.
Notice that there is no rejection of the idea that time and space to think can matter. There is no rejection of the GM (MC) incorporating their ideas into their prep.
And notice how there is a clear statement of the
purpose of the prep: to give the GM interesting things to say.
This feeds into the game's basic procedure of play, which requires the GM to
say things at certain times - things about what happens next in the fiction. The purpose of prep is to give the GM those things to say. This is elaborated on p 142:
[M]ake moves for your threats exactly like you make your regular moves:
• When it’s time for you to talk, choose a move (a regular move or a threat move, it makes no difference) and make it happen.
• If the players have handed you a golden opportunity (like if they blow a roll, or if they let you set something up and follow through on it), make as hard and direct a move as you like, the more irrevocable the better. Otherwise, make your move to set yourself up and to offer them the opportunity to react.
• Address yourself to the character not the player, misdirect, and never speak your move’s name. Always.
Now, the GM doesn't just make up fronts willy-nilly. The making of fronts happens
after the first session, as is explained on p 132:
After the 1st session:
Not, like, immediately after. Give it some time to sink in. I generally think about it idly all through work the next day.
See the list of resources? Listing each threat’s available resources will give you insight into who they are, what they need, and what they can do to get it. It’s especially useful to give some threats resources that the PCs need but don’t have.
Now go back over it all. Pull it into its pieces. Solidify them into threats, following the rules in the next chapter - so now, in the cold light of day, are Uncle’s raiders really a hunting pack, or are they sybarites instead? Are Bran’s crew a family after all, or are they something weirder, like Carna is a hive queen and Pamming and Thuy are her drones? Are the burn flats a furnace or a breeding pit?
Take these solid threats and build them up into fronts. Take the things you wonder about and rewrite them as stakes. Add countdowns and custom moves as you need.
The rules for fronts and threats follow, next chapter . . .
At an appropriate level of abstraction, this can be seen to be similar to the collaborative approach for establishing setting and situation found in Burning Wheel. At a more fine-grained level of technical analysis, it is different of course, and more precisely structured.
But it does show that the notion that AW (and similar games) eschew the GM contributing ideas is simply false. As I have posted many, many times before, what distinguishes these RPGs is their processes of play:
how ideas are created,
when and why they are brought "onto the stage",
how those ideas are used in action resolution, etc.
