A37575, let it go, you're like an OC dog who won't stop chasing that tennis ball...
You're confusing many things bringing the Air North crash into it yet debating mixture cuts at the same time. Who gives a flying f$&@ whether you use the mixture or throttle in a piston - the killer, literally, it the circumstances whe the simulated failure occurs. Mishandling at low level or slow airspeed kills people, not the fact the mixture was used. Guess what, in every light twin I simulated engine failures in, riching the mixture would instantly provide power. Not saying this will happen for every twin in the world, but I did the research and it worked for the light twins I flew - which probably make up 90% of the twin training market.
Go up in your typical twin trainer and experiment mixture vs throttle and the rubbish you're talking about windmilling. The prop will 'windmill' no matter the technique until a zero thrust setting is used. The mixture has to be richened for this setting even if the idle cut was originally used.
Go back and re-read the informed posts on the previous pages which explain why pulling the mixture isnt 'shutting down' the engine.
Then go have a beer, chill out and worry about yourself instead of trying to change everyone. If you want to stick to throttle cuts, go for it, but don't crucify those who use mixture cuts after considering the engine, aircraft type and how they'll set zero thrust as per the AFM. And if CASA's FOIs all have different opinions about 'how' to simulate the failure, what chance do us mere mortals have?
The topic that should be debated is 'low level simulated engine failures' In general - leave the initial failure technique out of it.