"Conclusions
A window of opportunity is now open but will soon close. In the United States, the Food and Drug Administration is developing regulations that will apply to e-cigarettes and vaporizers, and European Union Member States are now transposing the Tobacco Products Directive into national laws. Once these regulations are in place, they will be very difficult to change. However, because harm reduction strategies are often misunderstood or rejected [14], there is a risk that e-cigarettes and vaporizers will be excessively regulated. Regulators must consider the unintended consequences of excessive regulation, and should be held accountable for any such consequences. Given that e-cigarettes and vaporizers are already much safer than combustible cigarettes, any benefit of regulations will be small, whereas the unintended consequences can have a large negative impact. Unfortunately, current proposals for regulation are often worse than the status quo. It is sad that this is happening with the help of some public health professionals, scientists and elected representatives of the people."

Many good points not just about EU & US Regulations but worldwide also.

BMC Medicine | Full text | E-cigarettes: methodological and ideological issues and research priorities