What does gross size have to do with flexibility?USMC = 3 X The entire ADF
Do you want me to continue ?
The Canberra class are no more flexible than the Wasp. Arguably the Wasp is more flexible because it has a lot more space and stuff in it.
Much of this argument is pretty misguided. The Canberra and Wasp are different in size and capability because they are designed to carry different types of amphibious groups. This is the great thing about the Canberra for the ADF: for the first time we have an amphibious capability built around what is needed rather than what was affordable or available.
Two Canberras (60kt) are designed to carry an Australian amphibious group of 2,000 soldiers and 12 MRH90s. The Wasp combined with a LPD and LSD (80kt) is designed to carry the USMC MEU. The MEU is about the same personnel strength (about 20% bigger with the landing craft which are USN) but has 31 shipboard aircraft.
The much bigger air component requires a bigger ship, more accommodations for Marine aviators and more crew for a bigger flight deck operation. The Canberra is also a much more modern ship design so has a range of efficiencies like the podded motors. The Wasp is fitted with a much better defensive system en par with an Anzac class frigate.
So they are quite different in the details. But no one in Australia has any right to complain about the Canberra. They will be the best ships we've ever had.