Questions already been answered but for what it's worth, I agree that SEP IFR for commercial operations is probably not a good thing. I don't have tens of thousands of hours and I have seen piston engines do weird things that I don't think a paying commercial passenger should be subject to. Privately however is a different story because everyone flying privately should be aware and capable of doing their own risk assessment.
Turbine engines I have no problem with and think that SET public transport ops should be allowed, but it's up to the people with often little aviation background to decide on that one.