The JAA ATPL syllabus is long and futile in many aspects. Just some examples are: The level of detail on A/C generators, certain (gyroscopic) instruments and many many more. Stuff more suited to people who design and build the damn things than us mere mortal pilots who are going to be pressing simple on/off/reset switches. No one on Earth can be expected to learn all that and retain it for life. This is the way the syllabus was written way back.
I don't believe for one minute you can pass the exams with a 75% grade just by reading the Oxford, Bristol or Jeppessen Course Notes/Books. It's fair to say that feedback questions push the average candidate's grade up by between 20-40%. On the other hand don't think following the above strategy alone is going to help you. Granted you'll pass the exams but it wont bring that peace of mind in preparation for your first interview. To me personally, there's no real telling of the candidates level of knowledge if he/she has a 85% grade or a 95% grade. Some just have the capacity to remember extremely well short term
- Big deal.