While I agree that this is right, your two objections are both explicitly addressed within the relevant chapter:
“As a first objection, how would you actually put the nano-wire in the desired position? Especially when you can’t even see it (otherwise the Death Eaters and Voldemort would see it too). One mistake would ruin the entire plan. What if the wind blows and moves your wire? If one of the Death Eaters moves a bit, and feels a weird stinging at the side of their neck?”
Harry first transfigures a much larger spiderweb, which also has the advantage of being much easier to move in place, and to not be noticed by people that are interacting with it.
“Another objection, when you pull the wire to kill/cripple your opponents, how far do you actually have to move it? Assuming dozen Death Eaters (I do not remember the exact number in the story), if you need 10 cm for an insta-kill, that’s 1.2 meters you need to do before the last one kills you. Sounds doable, but also like something that could possibly go wrong.”
Indeed, which is why Harry was waving the web into an intervowen circle that contracts simultaneously in all directions.
Obviously things could have still gone wrong, and Eliezer has explicitly acknowledged that HPMOR is a world in which complicated plans definitely succeed a lot more than they would in the normal world, but he did try to at least cover the obvious ways things could go wrong.
While I agree that this is right, your two objections are both explicitly addressed within the relevant chapter:
“As a first objection, how would you actually put the nano-wire in the desired position? Especially when you can’t even see it (otherwise the Death Eaters and Voldemort would see it too). One mistake would ruin the entire plan. What if the wind blows and moves your wire? If one of the Death Eaters moves a bit, and feels a weird stinging at the side of their neck?”
Harry first transfigures a much larger spiderweb, which also has the advantage of being much easier to move in place, and to not be noticed by people that are interacting with it.
“Another objection, when you pull the wire to kill/cripple your opponents, how far do you actually have to move it? Assuming dozen Death Eaters (I do not remember the exact number in the story), if you need 10 cm for an insta-kill, that’s 1.2 meters you need to do before the last one kills you. Sounds doable, but also like something that could possibly go wrong.”
Indeed, which is why Harry was waving the web into an intervowen circle that contracts simultaneously in all directions.
Obviously things could have still gone wrong, and Eliezer has explicitly acknowledged that HPMOR is a world in which complicated plans definitely succeed a lot more than they would in the normal world, but he did try to at least cover the obvious ways things could go wrong.
I have covered both of your spoilers in spoiler tags (“>!”).