It’s pretty obvious than enlargement went too fast and is an utter failure. It was mostly pushed by the UK which wanted to weaken the union as a political entity as much as possible.

It’s even more true with the euro zone where some members are directly harmed by the high exchange rate.

It would make a lot of sense to go back to a smaller more integrated union with the countries which want it and leave the ones which only want the single market be part of a less integrated union.

Then again, considering Germany and France disagree about pretty much everything at the moment, I doubt it would go very far.