And I am certain there are other manufacturers "recommending" mixture cuts, exactly like Lycoming still does,
The topic of the thread being
low altitude failures, please elaborate who still does this? Proof talks, "I'm certain" walks.
Lycoming, no
Of course, this was intended for the higher altitudes where a complete engine shut-down could be conducted safely.
Have you actually ever had an engine failure?
Slow retardation of the throttle is IMO not a realistic training environment.
In my experience, not opinion, three failures, and none were a sudden catastrophic failure.
Using the mixture provides a better confirmation that the student is identifying the correct engine (they have to play with the throttles and the wrong selection is immediately obvious), but why not do this at 2 or 3 thousand feet, where there's enough height to counter an actual failure?