Robdean,
thank you for that insightful post.
I think I've seen some of the things I've posted before reflected here.
The main theme to me would be: build the automation around human capabilities rather than try to teach humans to accept the way the automation works.
When you say that by the time they were on the ground and spoilers were not deploying and brakes were not working, the thrust lever was a thing of the past, I think this should lead to a critical design rule when working with security related systems where a human has to decide in seconds:
One function - one dedicated control.
In this critical situation, asking people to memorize the GS/AB logic as solely coupled to the thrust levers clearly requires more brain cycles and, more than that, higher brain functions than "no spoilers - manual spoiler override lever". We are extremely good at learning simple "stimulus - action" tasks into what is called "procedural memory" while situational analysis requires knowledge that is accessed in "declarative memory". Much slower, much more prone to error and forgetfulness (we don't forget what is in declarative memory, like riding a bicycle or, actually, flying a plane) but sometime we do forget how things are tied together under the hood.
pj