It would seem to me that the root cause of the issues around the MAX are most obviously demonstrated with the rudder cable issue. The issue is black and white, the MAX does not meet certification standards.
So, the question is how was the decision made to grant a let from the certification requirements
What should be: ODA's demonstrate and document compliance with the certification standards. The regulator has to sign off on any deviation from those standards and they alone get to make the call
What was: ODA's decided that compliance was not necessary and the FAA said OK without any apparent review.
It is hard not to think that this is the culture that made something like the MCAS fiasco inevitable and now the genie is out of the bottle. It sure seems like the deeper people dig into how this aircraft got certified the uglier it gets
Here is something else to think about. How come it is OK that the MAX is the only in production airliner anywhere that does not have the capability of separating the Captains and Copilots control wheel/stick in the event of a control jam.