EU member states on the local levels have serious disadvantages as well. Non EU states can trade with other countries as long as they comply with their own countries guidelines. The EU member state producers have to comply with the EU regulations for trade which are much more complicated and detailed than most individual countries laws. The ideal situation for the UK, should they leave the EU, would be taking a position like Norway or Switzerland. These countries maintain a free trade agreement with the European Union, but can trade with non EU states freely.
The transition from the EEC to the EU brought about several changes to goals and policy that would alter its role in the European economy but also in European politics. The EEC was a purely economic powerhouse for European countries, facilitating free trade without interfering in political affairs. Now that EU influence has gotten much larger and grown to include 28 countries, they have expanded politically in order to stabilize member countries and keep them "on par" with each other. (Europa) More than anything, the EU is a political project, moving from what members thought was just a "free trade zone", it is transforming into more of a "United States of Europe"(Quora). The EU even has its own foreign policy, which has been known to conflict with some member countries own foreign policy. The EU is seen as taking power away from national level, acting like its own government even though it is obviously not its own state. The UK already has a special place in the EU, special exceptions and rules are made to accommodate Britain like the implantation of the Euro. .
Other member countries integrity and success(or failure) effects as well as depends on the other EU countries performance. Since countries like Greece are still apart of the organization, they drag down the economic stability and value of the Euro; on the other end of the spectrum, Germany is the powerhouse of the Euro, always bailing out Greece and essentially carrying the Euro's value while several others drag it down.