What’s successful? The fact that he compared a peaceful nation to one building an empire? Are you implying that Germany is going to start another world war? Hardly similar mentality is it? They’re not trying to wrest democracy away from all other countries. Sure you can argue for the definition of imperialism being extending power by various means but if Germany fit that then so does the UK, US, Russia and basically any major nation on Earth.
The EU is not solely controlled by the Germans so that would counter the empire definition. Sure they have a lot of influence but so do France and the UK before Brexit.
The single supreme authority would apply a lack of democracy, which the EU is not. You could argue the whole Brussels controlling everything think but the same could be argued for Westminster etc.