Hi Neptune, the arleigh burkes where designed to be operated in conjunction with a carrier task force and fulfill the US requirements, basically overkill for the RAN. To meet the RAN interests the arliegh burkes would have had to be reworked from the ground up to meet Australian Navy requirements this is where it wasn't a proven design and would have required much more testing and money.
This might explain it better than me, I just like the lines and that its Asutralian

"The Hobart Class Air Warfare Destroyer (AWD) will be one of the world’s most capable multi-purpose warships.
In selecting the Navantia-designed F100 as the baseline platform design and coupling it with the Aegis Weapon System, the Australian Government has ensured tomorrow’s Navy has the best equipment to defend Australia and its national interests.
Since entering service with the Spanish Armada, F100s have worked alongside US forces in the Persian Gulf as the first foreign Aegis equipped ships to be fully integrated into a US Navy Carrier Strike Group and have successfully been deployed as the flagship of NATO’s Maritime Group Standing Reaction Force.
The Hobart Class AWDs, which are under construction at three shipyards in Newcastle (NSW), Williamstown (Victoria) and Osborne (South Australia) will provide air defence for accompanying ships in addition to land forces and infrastructure in coastal areas, and for self-protection against missiles and aircraft.
They will be capable across the full spectrum of joint maritime operations, from area air defence and escort duties, right through to peacetime national tasking and diplomatic missions.
The AWDs’ Hobart Class Combat System, built around the Aegis Weapon System incorporating the state-of-the-art phased array radar, AN/ SPY 1D(V), will provide an advanced air defence system capable of engaging enemy aircraft and missiles at ranges in excess of 150 kilometres.
The AWDs will carry a helicopter for surveillance and response to support key warfare areas. The surface warfare function will include long range anti-ship missiles and a naval gun capable of firing extended range munitions in support of land forces.
They will also be able to conduct Undersea Warfare and will be equipped with modern sonar systems, decoys, surface-launched torpedoes and an array of effective close-in defensive weapons. These capabilities will ensure the AWDs have the layered defensive and offensive resources required to counter conventional and asymmetric threats.
The Hobart Class Combat System will be amongst the most advanced maritime warfare capabilities available and ensure the RAN has unprecedented levels of interoperability with Australia’s allies.
When Australia’s AWDs enter service in the next decade, they’ll be part of a fleet of around 100 Aegis equipped ships operating across the globe and will spearhead a quantum leap in the RAN’s air warfare capability."
Thanks for liking my styrene box! It's my cheap and light solution for keeping the model steady in the car. Ill eventually make up a box so the ship can travel inside that which will have a foam base and cradle to support her. This will be attached to roofracks on my car. As she is she will fit in the boot of my car with the one of the backseats down comfortably, it will just be a pain getting her in and out once detail is added, so the box and roofrack will make it an easier operation. The bridge superstructure and mast will be built as one piece which can travel in the backseat

She's not small at all coming in at 193cm overall length and 24.5cm beam so very beamy and only slightly smaller than an arleigh Burke.
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1/72 Arleigh Burke flight iia
1/72 Hobart class AWD HMAS Brisbane
http://www.shipmodels.info/mws_forum/viewtopic.php?f=13&t=1547671/72 Friesland
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