Beags
Are you being deliberately provocative or did you actually spend too long in 2/38 Gp?
If they are still alive to enjoy a career at the end of such a foolish experiment!
As the E3 and Nimrod fleets have proven over many years what you say here is utter:
There was an earlier post regarding the RHS Capt not being able to see the Eng's panel (sorry can't find it quickly to quote). More bolleaux, try it in the cramped confines of the Mighty Bunter. If it can be done there, it can be done in the spacious luxury of the 10 or TriMotor!
There are significant benefits to cross training, not least for career progression (for those that want it). Look around that station somewhere near you in Oxon and you will see a plethora of Nav bosses and flt cdrs. Even OC Ops and the Staish are Navs. Why? Because 2 Gp is still hide bound by the "co-pilots aren't fit for promotion" mentality. That disadvantages co pilots wrt navs, hence fewer pilots getting promoted (if they want it) and therefore a tendency to leave at 38 to the airlines. Then you get 2 Gp as a self perpetuating Nav empire. Take a look at the Gp HQ and play "spot the pilot".
Tonks the reason the airlines don't do it is because of money (but then this idea is apprently be promoted as a cost saving measure!! Counter intuitive?) How about the reason the airlines don't do it is because the average first officer is less well trained than the average co-pilot? (Provocative I know and I am NOT trying to be disrespectful of airline first officers). But military training (short though it now is) concentrates on building airmanship and captaincy and trains all to a first pilot standard (look at the Jetstream/King Air course. It is well removed from what we did). 2 Gp are the ones stuck in the past. No-one has yet come up with a good reason for not training both pilots in both seats (other than perhaps the double asymmetric max cross wind case for the C130)! None for the jet fleets.