A key feature of Dungeon World is that the players have known moves available, which - when used - can generate obligations on the GM to be truthful.
In RPG terms, I find that the antithesis of an approach that says (for instance) that the GM makes up the DC in response to the player's check; or the GM lets the player roll the dice but has already secretly decided what the outcome will be.
5e can, perhaps, be played in a DW style, but I don't think it defaults to it, at least not on the basis of the GMing advice presented in the playtest. The version of D&D that plays most like DW (or Fate, for that matter) is, I think, 4e, although 4e treats fictional positioning in resolution differently from DW.
In 4e the italic "fluff" can perhaps be ignored, but the keywords of an ability or power are quite fundamental to understanding how it works in the fiction, and to adjudicating its use. For instance, the reason a fireball sets things on fire isn't because the "fluff" tells us, but because (i) it does fire damage, and (ii) the caster can't discriminate in who it targets ("creatures", not "enemies").
The interplay between keywords and the fiction is one of they key ways in which 4e differs from a boardgame (where there is no fiction). It is how 4e handles fictional positioning as a contribution to action resolution. Just as in other editions of D&D, or games like DW or Fate, the GM is in charge of adjudicating the fictional positioning. But like those other games, 4e takes for granted that the GM will do this honestly, and that the players will be able to get the benefits of the "moves" the game gives them (ie PCs' powers).
I strongly agree with this, and I think it's not a coincidence that the 4e fireball description is very similar to the B/X one, and much more like it than like the AD&D one.
I think the AD&D approach to fireball is an instance of taking one particular GM's (and table's) play experience and trying to turn it into a universal rule for everyone. I don't think that's good for the game. Let the table work out what the effect on any given pile of metal is, of taking Xd6 damage.
The key thing, for me, is that the players should have moves that they can perform to play the game. If those moves are defined by reference to ingame phenomena like units of time or distance, or the presence of trees or animals, or whatever, then in order to use their moves the players need to have reliable ways of establishing what the relevant phenomena are.
But if, for instance, everyone things it's too boring, in actual play, to keep track of every 6 seconds that passes in the gameworld, or to keep track of distances down to the last 5', then my strong preference is not to use rules that are defined in such terms. Because if the rules are defined in such terms, but the passage of time or distance is a matter of GM fiat rather than actual counting, then the players can't really make their moves anymore.
This becomes obvious when you have, say, a trap that attacks everyone in 5', but no one is keeping precise track of which PC is within 5' of who and what, and then the trap is triggered and suddenly it has to be decided which PCs are affected and which are not. In practice, one solution I've seen used is to roll a "luck die" - everyone who rolls less than 50% (or whatever) is targeted; the rest are safely outside the blast radius. But in that case why are we taking the detour through rules that talk about a 5' blast radius? Just state that the trap attacks everyone in the party, but all but the triggering PC get a saving throw of 11+ to avoid the attack!
This is one strength of a system like Fate, at least in my opinion. (DW has some of these strengths too.)
This is an empirical claim which is open to serious question. As we've already seen in the context of 5e, reliance on a simulationist approach to ingame time and ingame space (detailed positioning rules, measuring effects in units of ingame time, etc) can be a very serious source of contention. And in my own RPGing experience, a significant amount of argument in many systems involves positioning in combat or similar situations (eg where is each PC when a trap is triggered). These arguments break out because the game system uses very simulationist resolution for positioning (eg each character is meant to be located at a defined point on a scale map).
In systems with abstract positioning, those sorts of arguments don't break out in the same way, because there is always an ascertainable answer as to where any given PC is in relation to effects that are generated. (Or in some systems, position becomes a type of keyword that can be used to feed into the resolution of an avoidance roll, or whatever.)
This is true. There are things I'm not good at as a GM (eg running Gygax-style dungeon crawls) and so I generally avoid them.
