The trouble with a procedure for an "if you get an UA, turn the FD off" procedure is that the aircraft may well be in the stall/UA and have relatively "normal" attitudes - e.g. AF447.
The FD was commanding fly up commands, and the crew faced a stall warning at similar time, with a 3° pitch (although subsequently it was mostly awry with higher pitch attitudes).
Airbuses and Embraers are smart in some areas (like dropping the FDs in extreme attitudes) but you still need to see through the FD in relatively normal attitudes at times. You may be in an upset and not have an extreme attitude.