I will probably be slapped down for saying this again, but the capabilities the F-35 brings makes small STVOL carriers worth while. As the F-35A demonstrates its synergies with AEGIS and naval platforms in general, I expect navies will become reluctant to go anywhere potentially threatening without them.
Perhaps our fleet could limit itself to war like ops within a couple of hundred nautical miles of a fighter base, as was planned post Melbourne, then again, how expensive would the F-35 actually be, as well as the ships to operate them? The new frigates are possibly going to have AEGIS back ends with scaled up CEAFAR, a large, strike length VLS and a pair of Romeos. A small carrier with space for maybe 20 aircraft, and a normal group of six or eight F-35B, two Romeo, a couple Sierras or MRH90s, as well as various UAVs or even ARHs, could even work out cheaper than the planned frigates.
Such a ship could replace the frigates one for one, say three carriers supporting six frigates (the original number planned under a Gillard and Abbott) and the three DDGs. They could reuse the CMS and other systems from the ANZACs and their aitlrgroups would consist of in service types, no extras. The only addition would be buying Bs instead of As, or UAVs for the final batch of new gear to replace the SHs.