While I can't pretend to know what the author of the quote in the question intended precisely, the top level of the wikipedia article on Fiscal Union gives just three main points. Unified tax policy, central set expenditure and collective debt issues via Eurobonds.
If fiscal union were to happen, national expenditure and tax rates would be set at European Council level. There would be Eurobonds instead of individual national bonds that would finance collective Euro debt.
Without implementing each of these points, the others are impossible or at least very difficult. The author seems to be suggesting that there is little point easing the borrowing pressure on countries such as Italy in the short term as without a long term plan for sharing the borrowing burden the cost of debt is going to rise again. And without a plan for centralising tax and expenditure rules, there is not going to be any move towards shared debt issuing that is seen as rewarding poor long term fiscal behaviour by the poorer southern Euro countries.
There seems to be a fair number of opinion pieces about this floating around at the moment. Guardian, Financial Times and OpenDemocracy popped to the top of my search list.
The FT summation for/against distills to this paragraph.
The danger that southern Europeans will feel abandoned by the north has to be set against the risk that northern Europeans will, at some later date, feel exploited by the south. The Italians and the Spanish rightly resent being caricatured as lazy, spendthrift southerners. But the opposite caricature of the rich, egotistical, arrogant northerners is also unfair — particularly when it is larded with references to Nazism and accusations of immorality.