In amongst the pedantry of whether failure to meet a "stick force gradient (or stick force stable slope) and its title is "§25.175 Demonstration of static longitudinal stability" means that we can call the aircraft unstable or not, I am surprised that there is so little comment about the potential wiring bundle chafing problem identified above, where if I understand it correctly it seems that a live wire could short to the to stab trim control and drive the stab trim to the stops - without the cutoff switches doing anything about it.
Coupled with the inability to stop it or to use the now tiny manual trim wheel , how many people fancy their chances of winning that argument with the aircraft ?
Just because it hasn't happened yet (205 million safe hours) doesn't mean that it won't happen as things age and fatigue (think pickle forks)