Yes I can see how Perth Airspace with Janadakot and Pearce makes it impossible to flow smoothly...
How LHR manage to do it with really busy Gatwick, Stansted and Luton in such close proximity AND lots of noise sensitive areas is an absolute wonder to behold!!
Either that or they just hope like hell..........
Let's face it, it's not the Airspace that can't be fixed it's the outdated proceedures you guys are forced to use?