Your forerunners did a spectacular job flying almost solo in twin- and four engine RAF transports/bombers from 1940-45. Not to forget the Canadians etc.
The SOPs then, even if worshiped at the 'altar of paper and ink', could not have prevented pilots from overriding it when needed. Those were normal procedures until over land when flak etc started a fire and engine failures.
Was the flight ops manual adhered to at the expense of survival? Abnormal situations and ATC handling happen quite often in peacetime.
Our 'Approach Check' is normally begun when 'slats/flaps 5' are extended. But if the approach is already briefed, why wait to read the details to each other when Approach Control is keeping us high on downwind for what might be a fairly short final, with various headings and we still need to identify the flying pilot's ILS freq. and comply with what might end up as a lousy, unknown intercept altitude etc? Tail de-icing must also be manually selected. The busiest time during the approach, slowing, turning and changing altitudes, is the worst time to read each other a few numbers-IF the DA is set, we have the correct ILS freq. and course window for the 'handling pilot'. With early vectors, the 'handling pilot' does not need to be any longer on the previous VOR freq, or have his course on the last enroute radial. The DA bug (decision alt.) should have been set during the descent or sooner, unless Approach asks us to use a different runway (remember-if you don't like the new option, just say "unable").The checklist can catch these at the best time.
The guys designing procedural changes at their desks at Fleet Standards etc DO NOT always KNOW what is the best time for us. A situation in a 122-seat narrowbody jet on a 30 minute leg (the 5th of the day) can change much faster than in a 350-seat widebody. Some of the 'procedure boys' mostly flew widebodies and never in a narrowbody with only two pilots. WE level off...WE twist the autopilot turn knob. In many of our planes, no computers are onboard, except for air data, EGPWS/TCAS etc. Ernest Gann has a chapter subtitle somewhere in "Fate Is The Hunter": "Books Will Not Cushion a Meeting of Metal And Rock"
, or words to that effect.