That’s basically what the stabiliser disconnect switches do on the 737. Pretty much all the controls are string and pulleys.
In any non-normal situation flying the aircraft manually usually comes at the expense of reduced capacity for troubleshooting and decision making. Deliberately increasing workload would be an unusual step to take.
The 737 Max accidents are (IMHO) mainly influenced by design choices that should never have passed certification and trying to slap a sticking plaster on top of those decisions is missing the bigger picture.