The quality of the sandstone around Sydney is governed primarily by location. Almost all of the sea cliffs are loose, chossy and otherwise unclimbable. There are a couple of patches of good rock (South Coogee, Clovelly, Diamond Bay and Barrenjoey in particular), but they are the exception rather than the rule. Inland crags tend to be on good rock, although the quality does vary and choss is relatively common.
Although there is nothing camparable to Nowra or the Blue Mountains, both areas are about 2 hours away, so when the suburban crags start getting tame, its not hard to expand your horizons.
For more detail on these and many more Sydney crags, surf over to the newly published Sun, Surf and Sandstone online guide book.