Migration is proof of the systemic failure caused by inability to adjust either interest or exchange rate. The first to leave is not unskilled labour but all the young professionals who are welcome everywhere and who can earn several times more if they do. But by hollowing out the destitute countries, they condemn the countries to worse destitution. Because the overhead of ageing population are not and cannot move anywhere, and they have to be fed by ever fewer youngsters remaining. The demographic bomb gets worse. (That bomb is already devastating Japan,and will cause us serious problems in time)
I have said previously, one of the only ways that would have helped the euro malaise is for Germany to leave. When the german taxpayers realise they are on the hook for an italian default, they will want to leave! It is interesting that there is a growing tide of investment analysts are also saying Germany should start distancing itself if it does not want to bail them all out. See holger schmitz in the express today, one of an increasing number of voices.
So if you ask what is the solution, the answer was ditch the euro.( Sadly what might have been options 5-10 years ago are too late to make any difference now.) The alternative of fiscal union would never be accepted now.