For one, I'm worried about what simple means. Likely something that will not make it as cheap to operate in every EU country, but make it as expensive to do that.
Also, whatever the EU commission/council/whatever they call themselves in order to not call themselves government decides has to be translated into local legislation by all member countries. So it will get twisted in 27 different ways, some of them incompatible. Also 9 of the 27 will take years to finish the process.