The biggest issue with flight manuals is the internal disconnect within CASA. From CAAP 54-1(2) "all aircraft must have the approved information necessary for the safe operation of the aircraft ...... The form and content of the information is that accepted and approved by the relevant NAA ..".
CAO 20.7.4 (and others in that series) require additional information to be supplied by the CofR holder. The whole philosophy of these CAO's is inconsistent with the use of the AFM/POH from the country of origin. It is impossible to comply with CAO 20.7.4 as it requires data per CAO 101.22 which was cancelled several years ago. The CAAP suggests that the data may be placed "in a convenient folder available to the pilot".
From the definition in CAAP 54-1(2) above - information for the safe operation of the aircraft is either in the AFM/POH or its not required full stop. The data required by CAO 20.7.4 should really be in a CASA approved supplement but that would mean replicating most of the old CASA AFM. The CAAP touches upon this subject in para 4.8.2.
"e.g. weight limitation for runway performance, requires approval by the authority, but is not required to be an AFM supplement, if the basic performance as detailed in the AFM can still be achieved." The later CASA guide to the new flight manuals doesn't address this subject. Even a Cessna 150 can't meet CAO 20.7.4 with the original AFM performance data. I would like to see a CASA example of a complete package meeting all of their requirements for a Cessna 150 then we can start discussing more complex airplanes.
From samples of new flight manuals that I've seen recently I'm quite sure that very few people in industry or CASA really understand the new rules of the game.
The second biggest issue is the question of retrospectivity. My aeroplane has been quite happy for the last 23 years with the old CASA flight manual. Why the need for change over for old aeroplanes if there's no other reason to amend the flight manual?