I'll need to check for relevant sources, but I'm fairly sure that the idea that boeing removed the "trim brake" is wrong. It's simply that the MCAS doesn't respect it. I think this is consistent with the Speed trim system which may be trimming opposite the pilot in normal operations.
And the reason MCAS doesn't respect it is because MCAS is designed to activate in high AoA situations. You get into a high AoA situation because you're already pulling back hard on the yoke, likely in an attempt to avoid something bad happening such as avoiding a collision. If MCAS did cutout when the yoke was pulled back hard, it would disable itself at precisely the time it is actually needed. This design decision does make sense. The real problem is not telling the pilots about it.
And the obvious solution is "tell pilots about it" which is going to piss off the public because a procedural change (training), a new UI to make it more obvious (like IIRC Southwest implemented) and a minor code fix (comparing the AOA sensors) will not satisfy everyone who's out for blood.
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