ATC watcher:
Somewhere down the line it would appear that very few people understand what " AR " really means, and I include myself in this.
No doubt about that. But, the crew was, or should have been, trained to understand it. Same for the aviation authority of Nepal. (although the approach was probably designed by experts outside of Nepal and, in fact, the aviation authority of Nepal may not have understood it, at least not as to the important nuances.)
But that said, I do not think one of the main cause of this accident was the displaced threshold.
Probably not. But, then again the illusions created by the airplane being in a vertical position in space at DA to land on a runway 400 feet closer could have been a contributing factor. hypothetical: "Reduce your descent, Captain, we are too low."