The release of these addresses would not be expected to make a significant change to the overall IPv4 exhaustion timeframes
Back of an envelope maths (http://labs.ripe.net/Members/kistel/images/userfiles-image-rir-speeds-201003-permonth-absolute-jagged%281%29.png) suggests that we'd get another 2 weeks, tops.
Disadvantages: - - If there were an unforeseen explosion of APNIC account holders in the the near future, there would be a slight risk that new Internet businesses might not be able to obtain IPv4 addresses for their business before IPv6 were generally deployed. However, historical data  indicates that this would seem a very unlikely scenario within a 10-year timeframe.
Is squeezing that last little bit of blood out of the stone worth it? -Mike