Three with a disagree algorithm is definitely what I’d expect out of such a critical system, but two with signal averaging would still be much better than just one.
Or alternatively with two, and disabling MCAS if they disagree, seems a better solution than having one and having no way to tell if it is working (keeping in mind both can still fail simultaneously). Not an ideal solution but better.
Unless I am misunderstanding what signal averaging is (quite possible) isn't it possible that in situations where the average of a signal is still going to crash the plane, a 50/50 guess is actually more likely to end up with a better chance?
If true, it's possible signal averaging isnt necessarily the best choice