If you think that the knowledge needed isn't perpinent you should give us deprived helicopter aspirants a thought. Since the CAA can't offer ATPL/CPL/IR helicopter specific exams I need to read up on things like the INS, fuel reserves for fixed-wing, how to navigate across the pond at FL330 and lot's of other stuff that doesn't apply to helicopters.
Helicopter students would probably be more knowledgable if the CAA would have kept all the national exams (instead of just POF and AGK as of today). Someone probably didn't like the idea that it would require less effort than the current syllabus. I guess that the "filter theory" was applied in order to force every student to study... just for the sake of it.