Beags :
I'm writing from a position well down the experience ladder, but surely the incorrect reaction of the crew to a single incorrect ADI display wasn't the sole cause of the accident - the defining one perhaps, but not the only one.
If the maintenance crew had decoded the fault code they would have been in a better position. They didn't have a copy, nor apparently did the KAL engineer.
If the crew hadn't been distracted before departure by an unfiled flightplan and all the other bits, they might have been more prepared.
If they HAD compared ADIs and the captain handed over to the FO then they would probably have not ended up impaling the aircraft.
I stand ready to be corrected.