Capt WE Johns I agree.
I and a huge number of peers flew SP IFR RPT in everything from Cessna 402s, Twin Otters and Bandierantes for years and years...the accidents we had, as a company, were more to do with the extreme flying conditions of PNG than anything else...those sort of accidents continue in PNG even though Twotters and bandits are no longer flown SP...and have not been for years.
But then Talair was a big company with all the positive things you attribute to that sort of structure. In her day Talair was the largest 3rd level (Reg 203) airline in the Southern Hemisphere...the average levels of multi engine experience of all the pilots but particularly the Check and Training staff was huge.
Whether SP is safe or not is down to training, experience and the maturity of the pilot concerned...without that you'd just kill an extra person, the F/O.
Chuck.