Flying in/out of unfamiliar territory is a known risk. Whether the 737 MAX series is higher risk or not is an unknown risk because of insufficient sample sizes.
Hopefully some statistician will start tabulating P values so we can see if the confidence intervals overlap or not. Treat this situation like a new "better" drug for X where 2 users died in quick succession. Is there enough evidence to take it off the market or not? AFAIK, nobody has (yet).
>If the delay's long enough to actually see parked aircraft brought into service, it'll largely be the same crews flying older 737s anyway.
Sorta. On a Canadian airline, Westjet, the MAX is flying routes that are too far for the regular 737s without a fuel-stop (by my estimates). I'm booked for such a flight in 2 months. I'll get to learn what happens. I would have been happy to fly the MAX8 based on the current lack of evidence for grounding.
Mostly people will just cancel their holidays or agree a teleconference because getting flights on that route at short notice is too difficult.