Not sure about the value of cameras showing pilot's actions in an emergency...
But Use of cameras to see if the inboard engine is still in one piece, check for fuel or hydrolic leaks, or if smoke is evident in the cargo hold seems to be a better use.
Also landing gear cameras could be used to check for fire following a hot and heavy emergency landing.
Would such good video "coverage" of the aircraft reduce the instances where slides are deployed as a precaution after a heavy landing, suspected hot wheel problem or suspected fire in hold?
The next step could be a smoke hood/mask with an option to display instruments. The system could also include a forward looking camera (physically protected from volcanic ash or hail damage until turned on) this camera could also have "night vision" sensor with its own roll and pitch sensor info overlaid as the last line of defence of smoke in the cockpit electrical failure at night. Such a camera could run independently on a small backup battery.
Does seem perverse that there are cameras for the punters to see whats going on but none specifically to help pilots.
Video can be encrypted so even engineers and managers can't view it.
However the public will wonder what pilots have to hide if too much of a fuss is made about privacy!