Jonty, I have practiced all manner of failures in my light twin days, including failures in the final turn, simulated "recovering" engines that can sucker you into trying to stretch the glide, etc. I even had a real one where when you raised the gear, the engine would stop, but it recovered once the gear was up and could be re-started (due to a bizarre hydraulic leak spraying the mags). Having flown a few light twins, I know that if it is heavy, you are often better off closing the throttles and putting it down as safely as possible- the idea that a light twin can always safely survive on one is a myth.
Point is, the most fundamental thing about flying ANY aeroplane is, don't stall. That is the most basic lesson we all learn- if you haven't learned it, you don't get to go solo.
In this case, it wasn't the health (or not) of an engine that killed people, it was simple lack of airspeed. It isn't, as you infer, a matter of skill, but a matter of judgement.