Missing the Point I think
You can certainly develop the existing conventional fleet of mediums and heavies...........however regardless of what you do you will always be a helicopter!!....with its normal limitations.
Offshore folk buy helicopter services on how much it will lift and how far it can haul that weight!!......speed is of a minor consequence.
If the 609 can lift the same weight as an existing heavy [With the heavies payload restricted due to full external and internal fuel tanks]......then it will be a winner by using its longer legs, and the passengers will love the lesser time in cruise.