My company wrote and printed its own flight manuals and checklists so the same company culture and operating policies would be consistent across the fleet
As did my first operator. Makes for a very easy training transition from aircraft A to aircraft C (just so folks don't think I'm in an A vs B rut). I did four conversions and the workload was reduced compared to learning a whole different protocol each time.
However, there is a significant admin and potential liability overhead associated with rewriting large scale documentation sets. Further, a simple aircraft can be made somewhat more complex to operate. In my observation, the F27 was modified to operate a bit like the jets .. so it ended up being a bit more involved than it needed to be.
I can't say just which is the best way to go .. swings and roundabouts might be the guts of it ? If one can address the high workload/stress situation in an emergency and the tendency to revert to initial training, possibly adopting the OEM way of doing things is a good place to start ?