//I think the plane has stability problems which may not be adequately corrected by computers (or pilots) taking over control. //
a "max" without MCAS would be perfectly flyable, it just handles differently and would therefore require a different training regime, and a separate airworthiness type certificate. Boeing didn't want that. the MCAS was intended to make the Max behave like a standard 737 and so save Boeing a shedload of cash on training, type certificates, etc etc.