F.E.D. re your post #9. I can add a historical data point.
During initial commercial S-61 FAA testing at the forward CG limit, the test crews had trouble making the required control delay time after a forward AFCS pitch channel hardover at max power, min speeed ( 40KIAS as I recall ).
The Ch Exp. Pilot got involved and went out to get the data point. Set up the condition right after takeoff, hardover was introduced and nose went down.....and down. Well, the aft stick input was finally made ( with authority ), easily meeting the required delay time, but the tail drive shaft suffered an intervention by a main blade, and an autorotation into an open field with 2 inches of snow resulted. A picture exists showing a perfectly straight line thru the snow made by the tail wheel. Instrumentation indicated a tail rotor Nr that could only be explained by autorotation.
So, the tail rotor autorotative state may not be all bad. The copilot for the flight was Dmitri ( Jimmy ) Viner for the historians out there.