It seems to me, Progressives would be better served by taking back control over their existing governments, rather than trusting these existing governments to create a new layer of government that is mainly held accountable via existing, democratic institutions that are already corrupt or at least highly suspect according to the Progressive analysis.

It doesn't have to be either/or. As the US shows - if there's a democratic deficit, almost any form of government will amplify it until it becomes an oligarchy which systematically excludes popular influence.

The difference with the EU is that there are signs the EU establishment is attempting to have a debate about this rather than assuming it as a given. The US, of course, doesn't want genuine populist democracy in the EU and has always worked hard to prevent it, both overtly and covertly.

Whatever democracy existed in the US - which has never been much, for the most part - is currently pointing stiff legs skywards. The EU still has some possibility of accomodating bottom-up influence - although with both regressive and progressive camps within the political structure, the outcome is still in the balance.