Great idea for discussion!
I'm in violent agreement with the 'limited exposure' concept.
We accept exposure to risk in helicopters in other areas that, on first glance, would take your breath away - this is on the quite reasonable point that it is actually a much lower risk than the other way of doing the job. Putting people onto tall power pylons is a good example - the risk from doing it by helicopter is far less than having the people climb up the pole.
To a certain extent, it's true for using helicopters to go to oil rigs.
We need to examine the engine failure rates and determine if the assumptions are still valid about rate of failure per 100,000 flight hour.
Can we also invoke the fixed wing single engine IFR / night logic? WIth the proper engine (read PT-6 for all intents and purposes) and the correct maintenance procedures, it's not accepted as being safer than twin piston light twins.
If we can show a substantial improvement in cost-effectiveness, then we need to explore it.
And anything to make it simpler to plan and fly such profiles is essential - trying to work out the parameters for Category A on some helicopters is enough to make John Kerry Republican...