There is one lesson I think we can take from this: we need to pay more attention to public debt levels. The Maastricht Treaty sets a public debt limit of 60% of GDP, although there is some flexibility. You can exceed this threshold, as long as you bring public debt back down to the 60% reference value. This limit must regain its prominence.
It is a recognisable benchmark, and allows countries the room to temporarily increase their debt during economic downturns. However, the pace at which countries are required to return to below this limit needs to vary more than it does now, taking their individual economic situation into account.