"why min speed reversion in that FLCH mode was not incorporated"
Below from the NTSB transcript. Sorry about the all caps and typos, that is how it was transcribed.
DID BOEING CONSIDER PUTTING ON AN AUTOMATIC AUTOTHROTTLE ACTIVATION AT A MINIMUM SPEED, REGARDLESS OF THE STATUS OF THE MODES?
(John Cashman, former Boeing chief test pilot during 777 development): WE CERTAINLY ALWAYS LOOK AT POSSIBILITIES. THE MAIN PROBLEM WITH THAT GOES BACK TO THAT ORIGINAL PHILOSOPHY -- NOT CHANGING MODES AND AUTOPILOT THAT THE PILOT IS NOT COMMAND. WHAT WOULD HAPPEN IF YOU JUST ACTIVATED THE THROTTLE IS YOU WOULD HAVE TWO CONTROLLERS OF ONE PARAMETER. THE AUTOPILOT WOULD BE CONTROLLING SPEED BY PITCHING, AND THE AUTOTHROTTLE WOULD BE CONTROLLING SPEED BY CHANGING THRUST. IT DOES NOT WORK FOR A WELL, SO YOU HAVE TO MAKE A MODE CHANGE, BUT THE AUTOPILOT IN A DIFFERENT CONTROL MODE, AND/OR THE TRUST. IT IS DIFFICULT TO DO, AND IT WAS VIOLATING ONE OF OUR FUNDAMENTAL FIND CONCEPTS.
>> CAPTAIN CASHMAN, YOU TALK ABOUT AUTOTHROTTLE WAKE UP. ISN'T THE ISSUE OF AUTOTHROTTLE FOR PROTECTION?
>> THE ENVELOPE PROTECTION OF THE AUTO ENGAGE OR WAKE-UP FUNCTION IS AN ELEMENT OF THE STALL PROTECTION, BUT IT IS NOT THE STALL PROTECTION SYSTEM. IN OTHER WORDS, IT IS RELATED TO OPERATION WHEN THE AUTOTHROTTLE IS TURNED OFF OR HAS BEEN DISENGAGED INADVERTENTLY OR A FAILURE TO DROP IT OFF, THAT IT WILL ENGAGE ITSELF. IT IS NOT A FUNCTION THAT IF THE AUTOTHROTTLE IS ALREADY IN ANOTHER MODE, IT WILL CHANGE THE MODE AND DO SOMETHING TO CONTROL SPEED. IT WAS REALLY THERE TO COME ALIVE AND ENGAGE ITSELF WHEN A HAD BEEN SELECTED OFF.
>> CAPTAIN CASHMAN, WHY NO AUTO THRUST PROTECTION IN -- MODE?
>> THE AUTOTHROTTLE PROTECTION FEATURE OR WAKE-UP FEATURE IS ONLY WHEN THE AUTOTHROTTLE IS TURNED OFF. IN A FLIGHT LEVEL CHANGE MODE, THE SPEED IS BEING CONTROLLED BY PITCHING THE AIRPLANE, NOT BY MOVING THE THROTTLE.
>> GIVEN THAT, THE SITUATION WHEN THE FLIGHT LEVEL CHANGES IN THE AUTOTHROTTLE IS AN HOLD, DO YOU CONSIDER THAT TO BE AN ERROR-TOLERANT DIVINE? -- DESIGN?
(Bob Myers, Boeing Chief of Flight Deck Engineering): I THINK I SHOULD REITERATE BRIEFLY WHAT CAPTAIN CASHMAN WAS TALKING ABOUT. WE LOOKED AT THIS DESIGN, AND WE WERE FACED WITH A DIVINE CHOICE. -- DESIGN CHOICE. IF WE GET A WAKE-UP OR A MODE TRANSITION OF THE AUTOTHROTTLE FOR A LOW-SPEED CONDITION, SAY, WE WOULD HAVE HAD CONDITION -- IN HOLD MODE FOR A LOW-SPEED CONDITION, WE HAD TO TRANSITION THE PILOTS AUTHORIZING THAT INCOME OWED-- IN COMMAND MODE CHANGE. THEY WOULD HAVE HAD TWO SYSTEMS CONTROLLING SPEED. WE HAD TO RECTIFY THAT SITUATION . IN THAT CASE, WE WOULD END UP WITH TWO MODE CHANGES AND A THRUST INCREASE, AND IF THIS LOW-SPEED CONDITION CAME ABOUT BECAUSE OF AN ENGINE PROBLEM, WE MIGHT ALSO BE PUSHING THRUST UP INTO THE ASYMMETRIC THRUST CONDITIONS. WE WOULD HAVE POTENTIALLY TWO MODE CHANGES UNCOMMITTED BY THE PILOT, A THRUST INCREASE, POSSIBLY ASYMMETRIC THRUST INCREASE, AND WE WOULD BE VIOLATING OUR PHILOSOPHY OF THE PILOT HAVING AUTHORITY. WE THOUGHT THE LESS CONFUSING OF THE SITUATIONS WAS THE DESIGN WE CHOSE.