Is it really the case that the A of A information fed to the stall protection system, which can cause full nose down stab trim, which cannot be overcome by elevator input, has only ONE source of data?
Many years ago, in the RAF, the Canberra had a number of tpi runaways, with fat al results, caused by malfunction if the single trim switch. This was cured by adding another switch in series, problem solved. Similarly we had an issue with stab trim runaways in the Valiant, and were trained to deal with the known problem, which could be overcome by elevator input.
But if Boeing are not giving crews the very last detail of the flight control system, they need to seriously review that decision.
With 20 years as a Boeing captain (73, 75 and 76) I have always held, and hold, Boeings in the highest regard, BUT, not giving pilots the full story about the most inportant system on the airplane seems a very strange decision indeed.