need an off switch
There are too many circumstances in which automation can be in control of some aspect of aircraft operation. If one of these instances goes wrong, it takes too long to identify which one has gone bad and run the appropriate procedure while under high crew task load. And that's if the aircraft builder has actually kept documentation up to date.
There should be a single switch that unconditionally inhibits all automation, returning full manual control to a pilot. Not a panacea, but it might have prevented this accident.