I think we have to distinguish here between e-bicycles and e-motorbikes. Regulations for e-bicycles are unlikely to become less restrictive because they are specifically designed to make them equivalent and compatible with ordinary bicycles so you can use them in exactly the same manner in all the same places. If anything they will get more restrictive after a few accidents and lawsuits. Regulations for e-motorbikes are covered by normal motorbike regulations as they should be. What causes confusion is labelling both as e-bikes when they are very different things.