When the EU was more a coalition of independent nations, it had vastly more influence and power in the world. The efforts to centralize power seem to be exactly what's causing the divisions. You have highly partisan leaders trying to dictate policy to countries that lean in very different directions. That's not going to lead to good things.

Stable empires have always been those that offered the greatest degrees of sovereignty to those under their rule, and I think that this should be somewhat self evident. When you try to enforce conformity across an empire, you're going to face resistance and even the mightiest of empires cannot sustain itself without a solid internal foundation.