The capacity factor issue is a cost issue. How many wind farms or solar installs are needed to provide the GWhrs of energy to meet load. Lower capacity factor, you obviously need more farms and it's more expensive.
But capacity factor is improving with designs and the ANU study is conservative on downward price pressure for renewables. So I think it all comes out in the wash. More or less.
Different out-turns on capacity factor might affect the mix of solar and wind, and it might require a bit more storage - battery/solar or hydro/pumped storage - but I think the price path is clear enough.
As far as reliability goes, obviously the worst case is those periods overnight and during sustained periods of widespread low wind. But with much more wind generation in future and more widely dispersed, and with more modern wind generators operating at lower wind speeds then the the percentage of minimum wind generation available at the worst times is going to be higher than now. So while there will always be aspects to quibble with, I can't see much argument that these analyses aren't validly supporting the viability of an all renewables grid. Open to other data and Rob is always good value, but I can;t see a major problem here.
