There is no sense in the proposal . The Westland 'D' outperforms the Boeing machine and that became more noticable with the introduction of ASPI.
There is no need for a massive increase in engine hp -the helicopter is pretty much at the limit of what it needed to carry and extra hp doesn't make it much more useful. All that extra hp will do is accelerate the fatigue process.
In terms of the Westland 'E' -Link 16 capability isn't a massive stretch in technology and many of the mods of the 'E' programme I am sure Boeing can devise a local modification programme. The real improvement that is needed is the improved nose gearboxes with better cooling and improvements to the MRGB.