My 2 cents (+gst) worth:
I hear your arguments about 2 being better than 1 when it stops, plus I think this argument has already been had on another thread, but it seems to me that the concept in use for the newish turboprop singles is reliability leading to an acceptable level of risk.
You can always crash and die in an aeroplane, so at some point you must decide what you're willing to accept in terms of risk factor when you get in one.
The same sort of idea is behind the approval of ETOPS for 2 engine airliners, isn't it; the demonstration of so many flying hours with no shutdowns?
If a PC12 is demonstrably and statistically as safe as a B200 (fatalities per flight hour over many hours) then it's probably a good solution, if it's economically attractive.
The old leveller that I say to my wife when she says flying is dangerous is that I'm probably at 10 times more risk in the car on the way to work than I am flying, but it still doesn't stop anyone driving.
