And without broader lists of potential complications for such rolls, and an explicit directive to the MC to make things shitty for the player characters, that's a hell of a lot of faith to put into the guy running the game, especially in a hobby where the idea of an antagonism between MC and players is still clinging on from it's modern originator.

This might seem how it feels sometimes from the player perspective, but if this is how you MC, you need to reread the book.

First, any time you game, from D&D to PbtA, you should have a trusted relationship with people at the table that you're not cheating, and you're playing the game by the rules to all have a good, and fairly balanced session. And if the MC is following the rules, they don't just 'fuck over' players on missed rolls, the make a move. If it's a Hard move, it's still a move. Let me explain.

"You fall on a bear" is Putting someone in a Spot. That's the Hard move. But now you as the MC have for some reason added in a bear to your campaign in exchange for the other dozen things you could have done to advance your own agenda. You didn't hurt the character (yet), you didn't move a threat on a front, you didn't take their stuff or capture or offer an opportunity... you took one path. And now, you don't just start talking about how the bear mauls the player... no. Your turn is up. because now, as stated explicitly on page 117, you ask "What do you do?"

The MC needs to remember that they're playing a game, too. And they have rules. If you want to advance your fronts, you need to be pushing the threats from your fronts. If you want to disarm, or trade harm for harm, or capture someone, that's what you do instead. But then the buck passes back over to the stars of our show, and they get to retalliate, or gain higher ground.

You're supposed to be a fan of the characters and rooting them on. But even if you somehow fail to do this, if your head is in the space of your nefarious villain, you should still be playing by the Move rules, and they have a fair shake to get their bearings.