I think we are making the same point in a round about way - at the moment all proper EMTB's offer their assistance in a broadly similar way, i.e you are not going to go out on a group ride with people on various bike, and find that certain riders are going to pull ahead based on the motor alone - motors with higher peak power outputs may change this.
I.E at the moment someone on an EMTB is faster than someone on a normal MTB up a hill, but only faster than someone else on an EMTB if they are fitter/putting more into the climb. With a bike like the new Flyon, will we see a spot between EMTB riders where by legally we are riding the same class bikes, but some can blast up hills a lot faster due to the higher peak power outputs.
The fact that the speed cut off point is different around the world, but the power classification is not, shows the confusion on this. I do believe they have to be regulated properly to ensure clear boundaries to ensure we can ride the bike, as you say, I just don't think the current regulations actually reflect the reality of riding the bikes.
With or without a motor there have always been people riding faster than others, what EMTB's bring into the equation is people riding faster in areas no one expected people to be riding faster, and from my experience that is higher average speeds in trail sections where you are not riding that fast.