Thanks for the detailed replies! It sounds like it’s working for you, but you’re leaning more on the “wound” mechanic than the actual moves. I can’t tell from your write up when you actually decide to go to “rolling for defeat” instead of assigning wounds. Sounds like it’s just a subjective choice, based on your gut and your assessment of the fictional situation. If I’m right, why don’t you feel comfortable doing the same thing for your enemies?
Do PCs often suffer multiple wounds? Are any of the “wounds” ever temporary things, like fictional positioning? Say, “your shield is trapped in its teeth”?
The way you flipped around my “threat rating” to make a hit point alternative for your threats should work fine. I’ve done that kind of thing before. (And note that all these techniques work for the total of the die roll as well as comparing each individual die! You can use a 2-12 scale instead of 1-5, and that works, too.)
However, it also seems close to what you were trying to avoid.
Here’s an alternative you could try. It comes down to eyeballing it, like you’re doing with PC defeat, but it gives a more disciplined way to do it:
By default, an enemy is defeated when an action that could put it down is carried out successfully. (If there’s a roll required, then this must be successful, of course.)
However, more dangerous enemies have one or more special features that make them much trickier to handle. To defeat such an enemy, you must find a way to neutralize each special feature.
For example, the Red Duke is a Legendary Swordsman. You can defeat him, but not in a fair sword fight. Unless you’re a legendary swordsman yourself, you’d have to disarm him, spend a long time studying his moves, or catch him off guard without his weapon, perhaps, before you could have a shot at defeating him. Otherwise, you’re just rolling to avoid having him take YOU out; he’s that dangerous.
A more dangerous enemy will have more. Perhaps that Chaos Demon you mentioned is cloaked in Hellish Flames, wears Demonforged Plate Mail, and regenerates any damage within moments.
To defeat it, they’d have to get creative. Maybe lure it into a consecrated space (where it can’t regenerate), douse it with holy water (putting out the flames), and tie it down so they can find a gap in its armor to make the blow which will send it back to Hell.
Of course, you can accept just about anything that seems like it would have a chance of working, and just make them roll for it. If they can come up with something that seems like it would neutralize all the monster moves/features in one move, then that’s great! Good luck, though.
In this format, your prep for each monster/enemy is just a list of features or moves. It could feel very organic. If you want to avoid writing things down, grab some tokens for the monster when a fight starts, and discard one each time they figure out how to neutralize a move or feature.
And it means learning about your enemy is important and useful to the players!