30 June deadline is an utter non-runner unless Revenue radically change their systems & get their own act together.
For example, it took several months this year for Revenue to organise pre-population of 2012 return PAYE/DSP data. If memory serves me correctly, it also took well into January for Revenue to make the ROS Form 11 return available. This should have been up within days of Budget 2013.
In addition, the increasingly creaky ROS Offline is no longer fit for purpose as an efficient tax return generation system. It was cutting edge 10 years ago but now needs a major facelift.