20c worth
Having flown and instructed on both sides of the fence in aircraft of various sizes, and having been a military instrument rating examiner, I would suggest that the current rules are about right. (I would even dare to suggest that some more training on weight and balance would be a worthwhile addition to the ADF pilot's knowledge before you try and blast off in a light twin using your CPL for example). After upteen years and 6000 hours in the military I recently did my ATPL exams and was greatful to learn more again!
There are significant cultural differences between the operations, which as a military pilot I did not understand until I had attempted both systems. There is a massive difference between operating in a multi crew environment and single pilot IFR, and remember that the avionics and systems at your disposal in civil light aircraft are often, regrettably, of a lower standard of serviceablility and accuracy than what you are used to, and every aircraft you fly will have a different fit and different switches.
The IREX is an exercise in semantics. My colleagues and I passed well first go after three days study. Many questions seemed unrelated to pure instrument flying, but were things that you should be aware of if you venture out into the world on your own particularly in the smaller flying schools and aircraft hire operators that . They often seem keen to throw the aeroplane at you before you are really ready (if you have that many hours in your logbook you must be able to handle this little aeroplane!). They still kill you just as dead. Without proper training in the civil way of doing things you will inevitably contravene the civil aviation regulations and harm your chances of that airline career. Can that pig driver finish his light aircraft trip at night under the VFR for instance?
I am not trying to have a go at anyone, but suggest you approach the experience of civil flying with an open mind. Anyway, thats about 40 cents worth.