If setting is largely indeterminate, then the Players actions and Move/Abilities will determine the fiction. However, if the setting is largely pre-determined, it will heavily constrain the the actions and outcomes of the Players.
[I]f there's a puzzle-trap in [Apocalypse World] as a result of a role, the MC can just ask how the character solves it or knows the solution: "I've dealt with Sand Mutants before, they always use the same snares." In D&D however, the trap is what is it is. While the party might come up with a clever solution to solving it, that solution is always heavy constrained by the specific details of the puzzle-trap. Fr'ex, touching the pressure plate with a ten-foot pole. But if that puzzle-trap says range 20ft, then the party is still effected.
I don't really see this as a problem, because, as I put it in the thread:
I wouldn't disagree, but this is when it starts to become interesting for somebody like me. When the players' actions are constrained, they have to think hard about how to do things. They have to brainstorm and come up with solutions. And when they overcome an obstacle, they feel like they really have overcome an obstacle.It's something I've noticed - and this may merely be a result of my GM-ing style, which doesn't have a heck of a lot of truck with "story" - that in my games, the moments when players seem to be investing the most emotionally, psychically, and psychologically in their characters are the moments when they are doing exactly what their characters are doing within the game. They may like combat because it's exciting and you get to roll lots of dice to see how many people you kill, (in fact they like dice-rolling in general), and they may like monsters and magic and big guns, but it's when they are "inhabiting" their characters that I think the game really comes into its own.
It's very 'gamist', but also in its own way very immersive, because the players invest a lot in this problem-solving aspect of the game, just as their in-game characters probably would.
And these moments happen in certain specific scenarios: when the players are deciding on a strategy, brainstorming plans, trying to solve a problem or puzzle, and (to a certain extent) interacting with an NPC. Those moments when the players are sitting around heatedly debating what to do next, and everyone is really involved in the process, offering opinions and counter-opinions and bickering, and you can just imagine their characters sitting around doing exactly the same thing in the game, are probably my favourite moments as a GM. I don't think it's an exaggeration to say that, really, it's what role playing's USP is.
But this arises at least in part through precisely the kind of restrictions talked about above. If you have a trap with concrete, specific details, the players are forced into doing precisely the kind of immersive problem-solving process I'm talking about. If you, however, have a system in which a player can just roll dice and posit a solution based on succeeding ("I've dealt with Sand Mutants before, they always use the same snares"), you lose the opportunity for that.
Which isn't to say that I don't like games like Apocalypse World or Blood & Honor, which don't restrict players with the setting the way that Old School D&D does. The setting-creation-through-play-by-ceding-narrative-rights-to-the-player thing they do is something I really enjoy. But at the same time they're missing something in limiting the opportunities for immersive brainstorming/strategising/problem-solving/arguing on the part of the players.
In any case, the discussion continues here and here. Food for thought, if nothing else.