There should be a certification class called 'Complex Types'. This will introduce a rule that prohibits the use of the real aircraft for training where the rehearsal of any system failure or malfunction is to be carried out.
The the thing is though Geoffers that it's not system failure rehearsal that's causing accidents and ditchings. It s very simple LLZ approach to a runway, or an approach to a rig at night, another low airspeed type poor handling ditching in Nigeria (Bristow 332L which has been kept quite quiet) or loss of lube pumps.
Apart from the loss of lube pumps, all of these have been line related. I see the deficiency as being in line training, for which there is of course still a role for simulators.