My partner and I just moved to the Netherlands and I mildly disagree. For one, we really like the diversity and appreciate the different cultures and histories. But I also think there's something to different member states getting to experiment on their own. Like, the Finns are onto something with their school system for sure, but the Dutch have a lot of Montessori schools--what are the pros and cons of each approach?

But, yeah not that we're wild about international train travel--that's a sore spot for sure. But generally we view the differences as a kind of richness and less of an inconvenience.