Agree. I think that he did try to barricade the door.
Sorry, I didn't do a very good job of conveying, but I was implying that there is no easy/cost effective answer. Otherwise I believe at least one of the really smart aerospace/business/government, etc bodies would have already implemented it.
I'm not sure for the slow decent, but there may be some sort of override for flap angle vs speed/altitude?? I believe they were saying on the radio that in the Egypt air incident that they discovered that one flap was X degrees up while the other was X degrees down, which can only be done with >50 pounds of opposing pressure on the sticks. ie one pilot yanking up to level out, and one pushing down to crash. Not sure of what all physical/electrical overrides exist.