The whole reason for all that austerity was that some countries were unable to refinance their debt and other countries are afraid they might not be able to refinance in the future. Refinancing debt in hard times becomes harder yet if it is externally financed.
You need to convince someone to lend you money if you want to run a deficit.
Love it or hate it, the Germans don't like a soft currency. The reason is probably the prelude to the rise of Hitler, which was marked by hyperinflation from printing too much money. It has been in their "DNA" since WW2, and no amount of economic handwaving is going to change that, at least in the forseeable future. In practice Germany has had a budget deficit nearly every year of course (such is politics), they just aren't that big.
The reason Germany joined the Eurozone was the absence of debt mutualisation. The Bundesbank warned that this was hard/impossible without political union, but they were ignored. And so, here we are.