Adopting a free floating currency so that countries aren't tied to other, more powerful countries but can instead let their economies grow at different speeds.
Politically?
Even if ignoring the EU side of it (which is nontrivial for various reasons not limited to defense, the vision of the EU, etc), is there a magic wand that would make the Greek government not be populist and wasteful with their own currency?
The problem with this is that Europe is not united. We have different languages, culture and histories. This is also what make Europe a beautiful, culturally rich place. The political elites are trying to impose a one size fits all model across Europe which won't work because we are not really all that united.
We don't have a common European demos that means that individual countries are fighting for their own interest and their is no overall strategy for Europe because the electorate doesn't really care about Europe, just what they get from being a part of it.
We really need to go back to being a trading block and to remove all of the political dictact and interference. If we really must have political unions, then they need to be between countries that share a common language so that the people can challenge their political masters collectively. This would mean Britian and Ireland, Germany and Austria, France and Belgium.
Euro as a common currency makes travel super convenient for example, not to mention the Schengen area and open borders.
Same could be said for certain regulations in health and sanitation for example, knowing you could rely on some forms of standards existing (however poorly implemented or not).
Also why would you make artificial barriers based on language, shouldn't the lines be formed based on culture and common understanding instead? Language is not what is preventing common people from participating in politics.
Language is preventing me from watching Austrian TV and phoning into their radio debates. That is, the population of Europe is silo'd whilst their political masters are attempting to work together. This is fractured because the electorate that place these politicians into positions of power cannot unite together to challenge them.
If there was a political union between the UK and Ireland then language wouldn't prevent me from calling an RTE show. We even already have a political party operating both in Westminster and Dublin - Sinn Féin.
Perhaps the various recommendations made in the late 80s and early 90s would be useful to reconsider. Hayek, for example, often suggested that the EEC could make every member nation's currency legal tender in all the others, to create a free market of currencies. He was a big fan of denationalising currencies anyway, and of having currencies compete against each other.
Another proposal on the table for many years was the idea of launching the Euro as a parallel currency to every nation's own currency. So, you could still pay your restaurant bills accross Europe with a single currency if you wanted to, but nations would still be able to fluctuate against it in case of trade surplus or deficit, the very thing that has been putting so much stress on the Euro's frequent deficit members (i.e. Greece, Portugal and Spain), and stress on the Euro itself.
Dude may be a great economist, but he clearly has no idea about ergonomics.
Like what, every store has to have twenty different cash drawers? This idea is _spectacularly_ poorly thought out.
This might seem sensible to many in Northern Europe, but I imagine that in the Mediterranean this is almost an attack on their culture. If countries like Britain and Germany want higher hygiene levels on the olive oil served in their restaurants then they can do that themselves but they shouldn't be imposing that onto Spain and Italy.
Part of the excitement on travelling to other countries is the differences; the longer the EU goes on with it's powertrip the more homogenised we will become.
Sometimes things go too far and then it's time to back off, but at the same time knowing that there's a good chance obviously dangerous things are banned is a good thing.