The travelling public need to be reassured that with professionalism the NAS system can work
One aspect of the NAS is that not all the participants are professionals, nor do they display "professionalism". They are, by definition, amatuers.
I would assume that a thorough cost/benefit analysis of the new system has been undertaken and that any extra risk is marginal
Never assume, it's
unprofessional . Read the various NAS threads and it will become painfully obvious that no genuine cost benefit analysis has been undertaken (especially Hansard record of evidence to Senate Committee- the CEO of AsA admits NAS may cost more!).
I haven't heard of too many mid airs in the USA
So if you don't hear about them, that's OK, or they don't happen? Suggest you look at some stats for the U.S. (average 35 aircraft per year lost in mid-airs), and also compare the "system" in the U.S. to NAS. The U.S. has a lot more infrastructure than oz. NAS is not the "U.S. system".
The vast majority of private pilots and training flights operate below 5,000 most of the time and away from CTA
Then why introduce NAS, which will have no benefit to the vast majority?
The system has been proven workable
I'd suggest that isn't true. The unique, never-been-tried-anywhere system called ausNAS, is already showing it's weaknesses.
Please, ponder what you have written.
Gunshy; although a valid point, I believe the more serious risk lies when aircraft climb and descend, as
every flight involves that. No error required.