My main focus is on the 'surprise' aspect.
It's true that the piston engine will generally warn us before a major failure, and of course, we should all aim for flight parameters that 'help' the autorotation (speed, rate of climb, height...).
It's also true that we learn a 'reaction' to move before we think.
And maybe that should just be 'get the collective down' asap.
Flare or not on entry - is it not a theoretical question ? Given the (huge) surprise of having to aurotate, I would agree to dropping the collective, then stabilising balance & speed - if the surprise is real, this is the reaction moving before my mind starts thinking.
To me, this (re)action should be as simple as possible. And practising this is how be build the re in the action no ?
A recent overspeeded engine failed for a friend (who was hovering and is OK) and real un-announced engine failures do happen.
It does seem that I might be right to be a little uneasy whilst VOR or COM twiddling, or even touching my map...
I cannot say that all the time I fly, I'm ready for it... I wish it was true but it's not.
If this was 3 or 4s then we're in another world no ? Is it only large turbines that can offer such a margin ?