欧盟整合

EU integration has made it an attractive large common market, but UK's exit in 2020 indicates that tighter integration's cost outweighs benefit, at least to some countries. Common complaints are democratic deficit, undue burden of bureaucracy, and erosion of sovereignty. 

It shows that a multi-speed EU is the way forward. 1) A federation at the core for member states wanting deeper integration, with common foreign, defence, fiscal and monetary policies. 2) A union as next tier for member states liking the status quo, without changing current rules and regulations. 3) A common market at the outer tier for non-member states wanting easy access to the EU market. 

EU is at crossroads. I'd say that France and Germany should merge and form a bilingual federation. Other EU member states can choose to join it any time or remain in the EU tier. In this way everyone gets the integration they want and be happy therefore after.