Surely (with specific reference to the written points) the ATSB is only making note of what is widely regarded as an industry norm elsewhere..with the possible exception of the US.
Yes single pilot IFR does produce good decision makers..but only if those pilots are taught too or taught how to reach a good decision.
How many of us can hand on heart from our GA days say that we were formally taught decision making skills? I certainly wasn't, what I did learn however was gleaned from the aeroclub bar, and from the odd sh1t-stained seat moments.
My opinion with the benefit of hindsight is that many of the skills that kept me alive in a SPIFR environment are of benefit flying mult-crew today...but plenty aren't..and have probably been trained out of me.
As for CRM, well that particular skill set requires an individual to want to be part of a team...something that single pilot stuff doesnt prepare you for, nor does it help with your management skills either IMHO.
No doubt though Mr Chuckles will jump on me now, and tell me I'm talking out of my arse
