The major factor they have in common has been a failure to perceive an indirect mode change or understand a confusing system failure in time to prevent an accident. Being able to manually fly a decent raw data ILS, or fly an arc within half a mile is not really that relevant. In fact it is presumptuous to suggest that the incident pilots weren't as skilled at manual flight as any of us.
But it is relevant. There have been numerous accidents and probably thousands of unreported incidents where mode confusion and consequent furrowing of brows have led to an "undesired state' in terms of WTF is happening now? What is alarming in these cases is the reluctance of the pilot to go Click-Click and manually correct the situation. In fact, wasn't this the whole point of the film featuring Captain Warren Vandenburg when he gave his briefing to American Airlines crews in 1997 through Children of the Magenta Line? He was concerned