the JAA exam content was wholly - or even substantially - relevant to flying, I would agree.
This whole business is designed for sorting the man from the sheep. The ground school is OK for the young and usually unemployed men who make up the bulk of JAA ATP candidates and who have the time to swat up. No aptitude is required (sub o-level intelligence is just fine for an ATPL) - just a lot of dedication.
I think when it comes to the CPL/ATPL stuff this is the case but the PPL stuff (which I think this thread started on) I think is very relevant and with the exception of the whizz wheel which should be done away with gives the pilot a good foundation in aviation.
Yes there are things that should be added to the theory like, NOTAM and self briefing. But the I think those things should be taught by the Instructor in a practical manner not by adding more theory elements. I also think that GPS navigation should be included in the General Nav.