To be fair I think that the 'drive' of the exams has changed. The old O levels would test you to see what you didn't know, the GCSE is designed to see what you do know IYSWIM. Kids are 'led' more, I remember essay questions, nothing like that now. My cousin did a CSE in the 60s in human biology and the question was , list the muscles involved in seeing and picking up a sixpence from the pavement. Something like that would never be used now.
I'm not knocking GCSE, but the jump to A level is vast and kids think that they can get away with a few weeks work, and there is just too much 'stuff' to understan and learn.