They had issues with the Iwo Jima LPH being an asset whose sole deployment capability was by air that they could not operate independently in Lebanon when anti aircraft fire became too great requiring them to first ferry them to ships that had well decks.
You end up spending a billion plus on a ship that could take aboard half the fleet air arm who could become a useless asset in certain situations if weather or ground conditions prevent the use of helicopters as the USMC has found to be the case. If you are going to be spending that sort of money on a ship you want something that is flexible, An LPH is not, an LHD is.
You miss the point of these ships entirely. Although they can be used as LPHs and for HADR, as they and ships such as the Invincibles, Garabaldi, Principe de Asturias etc. were designed to be. Over the years numerous other ships have been employed as required, for example HMAS Melbourne deploying to Darwin post Cyclone Tracy, USS Dwight D. Eisenhower being used to deploy the 1st brigade 10th Mountain Division (including 54 Blackhawks) in Haiti in 1994. Big ships with long flight decks have a level of versatility a frigate, destroyer battleship, STUFT (ships taken up from trade) can never have.
Such a ship, designed without a docking well, can be smaller and cheaper than one of equivalent aviation capacity that is required to have one. Higher speed, lower fuel burn, better seakeeping and far better adapted to the requirements of operating aircraft. Such ships are also ideal for command, control and communications, just look at the profiles of Blue Ridge, Northampton etc. the large flat deck makes for minimal interference with the vast array of communications equipment, while the large volume easily accommodates the required staff teams.
I said can be smaller and cheaper than an LHD but they can also use the money saved on deleting the dock to enhance the combat system and or increase the size of the ship. Izumo is larger but cheaper than Hyuga through deleting the VLS and some combat system functions determined not the be necessary, Hyuga and Ise having them allows them to make up for short falls in the capability of some of the JMSDFs older escorts, while Izumo can be deployed with newer more capable vessels. Too me a smaller navy like Australia probably should look to enhance the capability of as many of our platforms as possible.
Too me a platform such as Hyuga is a no brainer for Australia, its primary role is enhancing the sea control capability of the RAN, providing command and control (in what ever acronym you so desire), being an aviation and ASW force multiplier (i.e. able to better deploy and support existing assets than any current in service platform), adding to the fleets censor coverage, local and possibly even area air defence. There is also the elephant in the room, potential to operate F-35B in the future.
This is a capability that has been put forward for the RAN on numerous occasions since the RN suggested Australia look as acquiring their conceptional escort cruiser instead of separate helicopter carriers and DDGs back in the early 60s.
https://www.bing.com/images/search?...ad1d79b3a5856c2e7aa519fde7c4f65fo0&ajaxhist=0
To my mind such remains a very sensible capability to acquire and retain.