namely giving himself an extended break in a comfy seat in 1st class and allowing the two FO's to complete the flight to ORD, sans the disruption of a diversion to MIA.
Yes that would have been an alternative solution.
If he is upset enough to have to do that, he is not in a mental state conducive to flying passengers. Your suggestion is nonsense.
Well that is the whole point. If the captain had steped-down he wouldn't be flying anyone. The suggested course of action would no doubt have had a negative impact on the captain's future career but so it seems have his actual actions. If someone had suggested, before this incident occured, that a captain might divert and land at an unscheduled airport just to off-load a member of cabin crew you would probably have described that as nonsense.