UNCTUOUS, with respect, rubbish. The problem is more deep seated than whether there is a button or a switch to engage the autopilot.
The switch tells you by lighting up whether it is engaged. The PFD tells you whether it is engaged (and in both the Ethiopian and Kenyan airlines cases that is what the PF SHOULD have been looking at).
The problem is that crews cannot hand fly on instruments. Period.
It is time ICAO, the insurance companies and airlines recognised this and started to do something about the problem because it is killing too many too often.