Jiml,
Your post is exactly on, the recording and understanding the pyramid of events that fortell an accident are one important (perhaps the most important) means of improving safety. Stats show that about 65 to 75% of all accidents are crew error in one form or another, and this will virtually zero that.
Regarding AB-139, the particular characteristics of that machine are not necessarily due to the regulations. Its extemely high OEI peformance is a design trait seleced by Agusta to meet a market segment's needs. I do think the awsome power margins will play havoc with its payload-range capabilities, because the extra power means much more fuel flow while in twin engine flight. It is up to the customers to decide what to buy, of course.
One switch that has not helped them is that the newest interpretations of JAR Ops has accepted small exposure windows on takeoff and landing, as long as the statistic probability of an engine failure is very small. For the S-92 we tossed out the -6 engine from the design because we thought the older JAR Ops would be in effect, calling for absolutely rock solid engine failure performance from rigs and small heliports. With the much smaller -6 engines, we would not have a very good rig OEI gross weight. We spent millions on the promise that JAR Ops would require hard OEI from rigs.
As ppruners might remember, I have advocated for the new softer OEI interpretations of JAR Ops (in spite of having poised the S-92 to meet it!) because it is actually correct, and less onerous on the operator. Thus the AB-139 might be over-powered for rig missions. Over-powered only in the way that extra power takes away some commercial advantage by absorbing some payload/range.