Contrary to you what you write, calm on financial markets was not restored thanks to the eurozone's austerity measures, rather it was restored after Trichet was replaced by Draghi, when the ECB finally accepted to play its role of central bank i.e. to be a lender of last resort.
It is not thanks to the OMT. The OMT was only the result of Germany twisting arms of France, Italy and Spain.
I suggest that you look at the evolution of the trade balance between Germany and its neighbors since 1999. And you should also look at the evolution of German labor cost, productivity and inflation since then. You will see that Germany started to accumulate huge surplus with its neighbors in 2002 when it implemented the Hartz reforms that reduced labor cost below the productivity gain and that helped to get a much lower inflation than the 2% required by the Maastricht treaty. Germany purposely implemented a beggar-you-neighbor policy that aimed at being much more competitive than other countries and gained market share at their expense. That is the main cause for the imbalance within the Eurozone. Germany was successful because its neighbors bought their products.
Today the European Commission would like everybody turn into a German-like economy. But it just cannot work because now no country is ready to import. It will just collapse the demand in Europe and depress the whole continent. Actually it is already happening.
You wrote: "American banking regulation had long kept US banks small and local" and then: "If the financial crisis reveals a structural problem in banking, it is more likely to come ... from too many financial institutions having become too big to fail."
Contrary to your conclusion, it seems to be a good argument for the Glass-Steagall act, in the sense that it prevented US banks from being too big to fail.