I like this concept, now how does one tell the difference between a tenacious insider with a crazy idea that just might work, and a tenacious insider with a horrible idea that they just won't let go of?
I don't know, but I agree with you that this is a good question.
Bad crazy ideas break any part of that description. The single hard thing is new science/research instead of engineering, or the new hard thing won't make the rest easier, or the new hard thing is supposed to get rid of all the other problems.