I agree with your summation of the issue of running LOP in commercial operations, pilots have high enough workload without adding to it
I suggest you go for a fly with a Navajo pilot on a commercial run to see how much workload he's under in the cruise. If they're struggling with the workload at this point they need to go back to a Warrior or something slower. What you will probably see from 10 different pilots is 10 different leaning techniques from peak EGT to 150 rich, to just GPH settings.