There's a lot to review here, but I believe the facts will point to pilot error. There's been an over-reliance on automated systems in all aircraft for about the past decade. ATP's (commercial air transport pilots) have, almost across the board, lost their stick and rudder skills. In a lot of cases, they're more IT Help Desk technicians than pilots (trying to debug sophisticated auto-fly systems instead of turning the damned things off and actually flying the airplane).
The investigations have barely begun on both these incidents, but I think it's fair to criticize Boeing for this particular system (and its apparently bad sensors that rank right up there with Airbus pitot tube sensors - see Air France 447, for example).
The bottom line, though, remains that bad software/sensors/processors/etc. should not be allowed to take an airplane out of the sky. Boeing implements that idea, Airbus does not. It's up to flight crews to trust their own stick and rudder skills over the software. My money on this latest example of an air disaster is that, like the Lion Air pilots before them, these pilots did not simply switch the automatic stall prevention system off and hand fly the aircraft. If they trained on Airbus aircraft before checking out in the Boeings, you can easily forgive them for that. On an Airbus there is no method of turning off such automated systems, hence no need to train for how to do so.
I don't want to sound like a complete Boeing apologizer here. There most likey/definitely is a design flaw in the auto-no-stall system, as there are in a whole host of automated systems. But, I think it fair to cut Boeing a little slack here because at least, if properly trained, the pilots could turn the automated systems off and hand fly the aircraft. Note that this is no guarantee of safe flight however! A lot (most?) of the commercial jockeys today are products of a society which has been infected with IT broadly and who, consequently, are more inclined to solve the "virtual" problems all the way into the ground rather than solve the "actual" problem of getting the aircraft back on the ground safely.
bcnu,
Mikem
It's mourning in America again.