My main issue is when the ATO throws in multiple unrelated failures and system faults at unlikely times
Multiple unrelated failures are specifically verboten by the CASA Testing Officers Manual.
With respect to SIDs and STARs, you would have to demonstrate them in a Private IFR so surely you should accept it on a MECIR?
CASA offers little in the way of standardisation across its various field offices, or across the FOIs who issue and renew ATO privileges.
Not sure this is correct either. At the last (mandatory) ATO PDP I attended, 9 of the 12 were CASA personnel.