Tullamarine
Parallel both runways,
Move international terminal over to the western side of the airport.
Sydney
Get rid of the stupid 16/34 curfew at night time
Newcastle
Upgrade to full international status
Hobart
Parallel taxiway for 12/30, to save all the taxi delays
New cross strips 09/27 & 06/24 for light aircraft when Cambridge goes in a few years time.
More ramp space in front of the terminal, gets very tight on the overnights.
Launceston
Get rid of the crappy terminal, doesn't that get a bunfight at Virgin/Tiger end on the afternoon turn around.
New Melbourne airport
Somewhere down in the SE catchment area, one of the fatest growing areas in Australia.
I suppose also a number of the regional airports will need upgrading to take the Virgin ERJ