This article written Benedicta Marzinotto, on Project Syndicate, explains what are the fragilities of the Euro Area despite all the structural reforms that has been accomplished. In case of a crisis, high indebted countries would face again high difficulties to maintain their stability. 
Despite recently experiencing an overall economic uptick, the eurozone remains fragile and uninsured against the risk of another crisis. And a major reason is that it is still vulnerable to asymmetric boom-and-bust cycles.
Simply put, while all eurozone members can benefit during good times, some suffer far more than others during busts. This means that whenever the next crisis hits, safety-conscious investors will flee from fiscally weak countries toward fiscally strong ones that have a proven track record of generating economic growth…..
Read the article here