Given the ever increasing down time, basic changes could and should be made:
1) Decommission MACS feature and replace by a change to the mechanical feel in the control run, to achieve higher stick load at higher AoA with no stabiliser input
2) Build in a standby trim motor and scrap the trim wheel (see MD-80 for example)
3) Start from scratch with the trim electric logic and simplify the cut-out, column cut-out and trim switch confusion
4) Test fly and certify trim runaway situations on Max and NG
5) Create a “difference” course and market it to future operators at an attractive price - free for present operators
6) Make public the above, certify the Max and recommend the trim mod to NG operators
Takes time - takes money? So do crashes and down time, as we see.