Its more complicated than this.
For example the Collins class uses a nuclear boat combat system and sensors, these consume more power but are more suitable for a boat out in the open ocean. European systems tend to be more power efficient smaller in scale, suiting a coastal submarine. This starts to extend the the entire design philosophy of the submarine. To the batteries, to the engines, to ventilation, to crewing.
Nuclear boats have essentially near unlimited power budgets, and this goes through the whole philosophy of every system. They can have very robust high power systems. Conventional submarines need to be more economical due to their more limited power budget.
At some point you need to pick where you want to be. For the RAN, regular surfacing isn't an issue, and fits in with their CONOPs. With a submarine you have limited volume and you have to make hard and fast design decisions that flow through the entire design. With the Submarine, how you intended to use it is very important.
Australia's whole thing is a forward defence. That is why we operate our air force out of Butterworth in Malaysia, Thousands of kilometres north of Australia. Our ships frequent ports in South East Asia. Australia is likely to take on operations that takes them directly into other nations waters. The key choke points lay thousands of kilometers north, there are not choke points around Australia in its waters.
Norway, adopts a European style defence, focused on their territorial waters and choke points there in. They are unlikely to taken on Russian subs in Russian waters They want something that can chase away and deter Russian incursions.
Canada needs to make some choices about what it needs and how it wants to operate. While a lot of noise is made about operating under ice, Canada has never had submarines designed to do that. Going from history, a long range conventional submarine would appear to be more inline with history of Canada's use of subs.
