Interesting read. So this accident made Bendix introduce the audio warning TRIM IN MOTION. I rented a 2005 C172 some weeks ago and I was annoyed by how long you have to push the buttons for the AP to take your command and the TRIM IN MOTION annunciation over the audio panel. Now I know why and it's actually quite a good solution.
Trim runaway errors are evil. My avionics guy told me about a situation they had in a
Fairchild Metroliner with trim runaway. This aircraft does not have a manual trim wheel and two pilots together were not strong in enough to pull back the elevator. Almost got killed.