It seems to me that if EASA, or one of the other international regulators, allow the MAX to be un-grounded/certified for flight within their airspace and a MAX subsequently crashes due to a MCAS related problem, the heads of the international regulators will be 'on the block' as well as those of the FAA regulators. In these circumstances, if I was an EASA regulator I would want to see for myself how the MAX performs at high AoA, without MCAS, before clearing the aircraft for flight within my jurisdiction. I would not be prepared to accept at face value any assurances given by the FAA or Boeing, if my job or reputation was on the line.
There are currently a number of 737-8 MAX aircraft located within EASA territory (TUI have 6). Could EASA regulators get their hands on one of these, take it to a test facility (e.g. Boscombe Down) and conduct their own 'bare airframe' tests to ensure there are no nasty surprises as far as MAX pitch stability is concerned? With a bit of temporary re-wiring of flap position input, it should be possible to fool the MAX computer into thinking the flap is down (when in fact the wings are 'clean') thereby disabling MCAS. This would allow the test pilots to explore the MAX flight envelope at high AoA in a 'bare airframe' configuration.
Surely, such due diligence is not too much to ask for from EASA to ensure the lives of European passengers are not exposed to undue risk. I'm not suggesting that EASA should conduct comprehensive re-certification flight tests, only an exploration of those aspects of the MAX flight characteristics which led to the introduction of MCAS.