This is an interesting point. Some will argue that the AOA disagree indicator wouldn't have made any difference in either crash. But it seems like it would have caused Lion Air to take their aircraft out of service and fix the problem after it occurred on the penultimate flight.

Of course, the fact that they kept the aircraft in service without bothering to diagnose the issue that almost got everyone killed on the previous flight is a counterargument in itself. There's more than enough gross negligence to go around in this case, unfortunately.

Edit: actually, it appears that Lion didn't spring for the "optional" warning indicator feature in the first place.