From what I understand, you are advocating a more refined mapping of influences, and then use them to adjust a general temperature rule based on latitude. Pretty much the same system as before, is this right?
As for Western Australia, I looked it up - and here's what I found:
https://en.wikipedia.org/wiki/Leeuwin_Current
I would say this return current is formed only in Australia because the continent doesn't block the incoming equatorial current from the Pacific, which, on top of it all, is pushed southwards by Indonesia/Borneo. West Australia is the only continental west coast without a cold current with upwelling and it is the only neighbouring a east-west through.
My logic and limited oceanography knowledge wouldn't let me predict this either, but it really makes sense (and I shall be updating my currents map accordingly
)