I fully agree that it's all speculation, and won't help to understand the causes.
However, I do find it interesting that the two seemingly remarkable eyewitness reports from the night of the accident: that the aircraft was "tumbling" and that the "rotors were not moving" could be consistent with each other.
If confirmed, then it strikes me as one of the most remarkable and unexpected accidents, and a rare case where eyewitness accounts might have been crucial in unravelling the process of the crash.
I suggest that no-one's tried to model a tumbling, crashing helicopter because no-one considered a helicopter would crash without its rotors turning, unless there was some sort of complete gearbox failure.