VFE,
Granted the ATPL examination system has it's faults in that you only ever probably use about 12%
I really disagree with this view. How can a pilot get along with knowing the law, how to predict and interpret met information, how a CSU functions, what happens if the static port is blocked, what the predictable instrument errors are, how hydraulics function, when a tyre is illegal, ILS limits, recognising stress & fatigue, etc, etc, etc.
Personally, I couldn't imagine getting along without Instruments & Systems, Gen and Rad Nav, Air Law and Met. A good proportion of the ATPLs are relevant to PPL flying never mind CPL/IR. I even find dollops of Human Factors relevant to the business world, never mind flying. The COMMs subjects are useful if only for highlighting gaps (however small) in knowledge.