I believe the RAF have looked into this on several occasions; perhaps someone can shed some light on their findings.
Can't speak for the current policy but in the 80's turnbacks were taught and practiced (on the Bulldog in the UAS world), to students with low 10's of hours.
There was an envelope for suitable wind component. The procedure required a steep gliding turn which needed a pronounced nose down attitude. Definitely achievable, have practiced it myself and also seen one happen 'in anger' due to an EFATO.
However, certainly a lot of scope for things to go wrong (but on the other hand, if the donkey has quit, things have already gone wrong.)
That said, in the absence of a definitive study,
by appropriately qualified individuals for a specific aircraft type, I wouldn't touch it with a bargepole.
i.e. the fact that I know its doable in a 'dog doesn't mean I'm dumb enough to claim its doable in anything else.
With regards to Hot n Highs second paragraph, the points are valid, but trainable.