Let’s build on this ogre example, assuming our PC is relatively inexperienced.
After an hour of searching, you find a large stone bridge over the rushing river. On the near bank guarding the entrance is a large, ten-foot tall ogre with a huge two-bladed axe. As you approach he grins and calls out to you:
“Two-hundred pieces of gold to cross my bridge!”
This sum represents all the money you’ve earned so far. Without it you won’t be able to afford an inn, let alone repairs to your armor and weapons. What do you do?
The goal here is to make it mechanically unlikely that the fighter will be able to take on and defeat the ogre without just making a pronouncement to that effect. I think Dungeon World can do this but it’s a bit tricky (part of this has to do with how the hack and slash move is written).
Let’s imagine our fighter has the following stats:
STR 16 (+2)
INT 9 (+0)
WIS 12 (+0)
DEX 13 (+1)
CON 15 (+1)
CHA 8 (-1)
So when this fighter rolls hack and slash they have a 42% chance of a 10+ (they deal damage without taking any), a 42% chance of a 7-9 (they deal damage and receive an attack in response), and a 16% chance of a 6- and something bad happening. In the ogre example, the DM’s best move is probably to add fictional requirements to be able to attack (e.g. roll defy danger with dexterity to get inside the ogre’s reach) or consequences to the ogre’s attacks (e.g. they don’t just hurt, they knock the fighter down, knock his breath out, terrify him, etc.).
The reason the latter aren’t as effective is that no matter how devastating the ogre’s counterattacks are there’s a 42% chance that they won’t happen (independent of how powerful the ogre is). The probability of consecutive 10+ results is reduced (~16% for back-to-back 10+), but if our hypothetical fighter can get an additional +1 bonus the probabilities become 58% for one 10+ result, 34% for two, and so on.
By contrast, if this fighter tries to bargain or trick the ogre (which might make more sense fictionally) they are rolling their worst stat (CHA) and have only an 8% chance of a 10+ and 42% chance of a 7-9. The DM doesn’t have an easy way to give them mechanical bonuses to the roll (or to reduce a difficulty) even though it targets one of the ogre’s weaknesses. The DM might forgo having a roll at all if they want to encourage the player to negotiate with the ogre rather than fighting it, but there isn’t a strong mechanical basis for this (i.e. it might not feel like a tactical success even if it is one narratively). The one silver lining is that a failed negotiation roll might be punished less harshly than a failed attack role by the DM.
In a symmetric system, you can just give the ogre a high STR score along with low INT and CHA scores, and let the player try whatever approach they want. Fighting might be more straightforward but it will be mechanically much tougher even for a very good fighter (but not impossible). The player can be sure that they will be on the receiving end of the ogre’s attacks (and that the likelihood of being hurt isn’t totally determined by their own skill and how well they roll). Bargaining or trickery will probably be much easier due to a reduced target difficulty, even for characters who aren’t usually as good at those kinds of skills. Assuming the odds of winning the fight are long our fighter might be happy with roughly 50/50 odds of coming out on top of a social contest or conflict.
Without variable target difficulty, the DM in Dungeon World has to lean very heavily on defy danger as well as other moves of varying hardness to try to communicate the risks to the player and make these actions feel dangerous. The DM can try to give +1 forward to moves that make fictional sense (e.g. tricking the ogre) but even there the bonus probably isn’t enough to make it attractive to characters who weren’t already committed to it. In those cases the DM will probably just want to grant the player success, which achieves the narrative goal but without an explicit contest. Our fighter may be induced to use diplomacy but they’ll be well aware that mechanically they are setting themselves up for failure if the DM starts calling for rolls.