Given the hideous prevalence of medical errors, and their known association to fatigue, I would far prefer a doctor chemically warded against fatigue to one without such armor.
No, the new equilibrium would be 96-hour shifts, with doctors to their physical limits and making as many errors (modulo differences in attention at constant fatigue induced by modafinil, if any).
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If it's worth saying, but not worth its own post (even in Discussion), then it goes here.