It occurs to me that the "bare airframe characteristics" issue may be at the bottom of the "phased approach" that Muilenburg talked about in the 3Q call, with FAA granting approval ahead of non-US regulators. Could the FAA be ready to accept Boeing's fail-safe Mk2 MCAS, with curbs and restraints imposed on the existing system and appropriate training, while ROW holds out for fail-operational Mk3, that also gets backfitted to the US fleet?
If so, there may be a long gap between FAA and ROW certification, and a lot of deeply unhappy bunnies in the global base, not to mention a Godawful image problem.