Interesting. In the UK the accident statistics confirm that there are more
serious injuries/fatalities/damaged gliders per 100000 launches by winch
than by aerotow!

Automatic transmissions would provide constant torque rather than tension
or speed. And then only at a fixed throttle setting.

The predominant accidents with winches are 1) wing drop during ground run;
pilots must release before the wing touches the ground 2) stall during
rotation, it is hard to know whether these are elected rotation or
automatic rotation 3) power loss below 100' and inappropriate pilot
response and 4) power loss mid launch.

Mechanical or electrical devices to maintain torque, speed or tension are
all very well in their place but there is no unique solution as different
conditions apply at different parts of the launch. There is no substitute
for pilot and winch driver training and awareness.

I recommend that all UK pilots read the annual BGA report on glider
accidents and that they promote the training initiatives from the BGA
which appear to be reducing the number of accident and incidents in our
sport.
Best wishes

JohnR-K