Been thinking on the RAN as per usual, cruisers, destroyers, the Washington treaty limitations and post WWII plans and needs, as well as how large and capable destroyers and destroyer leaders became during and after WWII through to the DLGs of the 60s and modern cruiser sized destroyers and frigates. Flyhawks 1/700 Naiad and Aurora have added some incentive for ideas.
What if somehow Australia ended WWII with a substantial number of small light cruisers based on the Arethusa, Dido and Bellona classes in service and building in addition to the frigates and corvettes and instead of the Tribal class destroyers, Hunt Class had been built instead. Maybe 6" and 5.25" ships could be built at Codoc and 4.5" versions at Williamstown.
Pre-war heavy and light cruisers plus destroyers were obsolescent and worn out, UK built J,K,N and war emergency destroyers returned post war and the only modern ships the very cramped Hunts, with no Tribal, Battle or Daring Class built, building or planned, the obvious solution was to adapt the light cruisers. The end result was the light cruisers were modernised, converted and completed in a variety of configurations including task force leader, carrier GP escort, ASW leader, and DL / large destroyer using the latest directed Bofors, US 3'/50, Limbo, new radars and directors and where applicable sonars (probably the incomplete ships).
Next step was complete the least progressed hulls as cruiser/destroyers (IAW the RN anti Sverdlov concept) and as they started entering service in the late 50s and early 60s the earlier post war completed vessels could begin being converted with Tartar etc. to replace the modernised war built ships.
Finally the design is evolved into a new build DLG during the 60s as an alternative to buying Counties. Initially with Tartar, later ships were built with Standard and the final Batch with Sea Dart.
Thirty years of evolution 6", 5.25", 4.5", 5"L54, 3'L50, 3"L70, maybe Mk26 6", Bofors 40mm, maybe Oto Melara 76mm Compato, or Bofors SAK. Tartar, Standard, maybe Terrier, Mk10, 11, 13, 22, or even 26 GMLS, Sea Dart, Seacat, maybe Seawolf, Limbo, Ikara, Super Ikara, or even ASROC a variety of British and American radars, directors, other sensor and systems. Sycamore, Whirlwind, Wessex, SeaKing, maybe Sea Sprite. Lots and lots of possibilities, maybe even a life extension for 1970s built ships seeing them serve into the 90s with NTU and Seahawk.