The concept of the nation-state is a fairly modern one, and flawed at that. The sovereiginity should be with the populos, regardless of which side of these internal imaginary lines they are born. As long as European nations continue to focus on their superficial differences there can be no voice speaking for the shared European values and intrests. Supranationalism is needed to form a progressive counter to powerhouses as the US, Russia, China and the upcoming economies. United we as the EU could change the world for the better, divided we will be subject to the whims of these other nations.
In order to form a more perfect union, some European countries will have to give up their sovereignty for better and stronger central government. The Euro zone already has one economy, but each country has their own defense. Common defenses, basic infrastructure and tax benefits can be had by giving up certain sovereign rights of the countries involved. The United States has been doing this for more than 200 years and Europe should be able to set aside regional and national issues in order to provide for the common good.
Taking away national sovereignty is a violation against human rights! Just look at previous powers who has done such things: the Roman Empire, Napoleon's Europe, Nazi Germany and the Soviet Union. Their cultures were not respected and the central rule was only interested in themselves rather than the people! No to any federalism and totalitarianism
The European Union provides various benefits to its member states, but it can become dominated by the more powerful countries in the union. It's not justifiable for countries to give away their national sovereignty to join the European Union. The Union isn't going to disappear anytime soon regardless of that fact though.