The fundamental promise made to customers (a more efficient 737 that doesn't require new pilot training) seems impossible to deliver at this point, and probably

The fundamental promise made to customers (a more efficient 737 that doesn't require new pilot training) seems impossible to deliver at this point, and probably wasn't possible from the outset. At this point they could probably still turn the 737 Max into a sellable product, but it will be different from the one promised if it requires a new type certification for pilots due to the different flight characteristics (which Boeing was trying to hide/minimize with MCAS).