In all actuality the real Future Air Navigation Systems will be tied into FMS allowing ATC to command and control an aircraft.
I doubt that ATC will ever have the authority to command and control the aircraft.
I can see how in the past there would have been an extreme privacy issue around FDR data but this should be revisited by ICAO and the manufacturers
Not sure why the extreme privacy issues have changed and in fact with the trend to litigation instead of safety enhnacemen, its even more reason not to allow FDR and CVR data to become less secure.
Maybe the solution is to use GPS tracking capabilities to make it easier to find the CVR and FDR. This would also be of assistance in locating the wreckage. If the latest ELTs have that function why can't it be built into the "black boxes"?