Umm dont really know that much about the real estate etc at Perth Airport, but why would they put the regional terminal next to the international terminal rather than the domestic one? Surely most regional punters connect to domestic flights rather than international ones (particularly the mine workers). Seems very odd.
And I love their picture of the new international terminal, complete with a QF A380 parked there... as if QF would ever fly the A380 to Perth, they can barely fill an A330 to/from there !!