◇ Could this help me?
Yes. The organizing principle is correct and unusually well expressed: the value of a heavyweight reasoning model shows up on problems with a large search space and a high cost of being wrong, and disappears on routine execution where a cheaper model produces the same result. The asymmetric-decisions case is the sharpest of the six, because it gives a genuine test for whether the expense is justified rather than a vague sense that the task feels important. The audit-and-handoff case is also practical, since having the expensive model produce the plan and a cheaper one execute it is the same routing logic applied deliberately. General practice.
I want to decide whether a task is worth spending my most expensive model on, rather than guessing. Take the task I describe below and assess it against six tests: does it need an audit that surfaces gaps I would miss, does it involve ambiguity where the data looks fine but something is off, would it benefit from adversarial review of my reasoning, is it an asymmetric decision where being wrong is very costly, does it require synthesizing many sources into one insight, and is it turning expertise into something concrete. Tell me which tests it passes and which it fails, and if it fails most of them, say plainly that a cheaper model should do it and what the prompt for that model should be.