I recently became much more pro-total-unification, so let me give you this counterpoint: individually, European nations are no match to the major superpowers, neither economically nor militarily. We'll get gutted by divide-and-conquer approach. In contrast, bound much closer together (particularly with some form of pan-european armed forces), the EU would become a proper global superpower and a counterbalance for the USA and China.

You cant really believe any of the EU countries actually want to work together? The EU was only possible with the premise of countries keeping their autonomy. Believe me when I say that us Germans would rather go to war than merge with France, just as an example.