Both of these suggestions assume central banks that are competent and non-malign. And if we had central bankers like that, the eurozone would not be in trouble.

The fix you are suggesting is to first break up the eurozone, and then replace the boards of the national banks with people who give a frack about the real economy and employment. But if you are willing to fire central bankers, why exactly do you need to break up the eurozone? Just go directly to the part of your perscription that is actually helpful, and sack the board of the ECB on grounds of incompetence.