PhD students often worry too much about what the examiner wants to see, distracting them from their own purpose. This results in ambiguous, unconfident writing, making it more likely that the examiner will be unhappy.
As a PhD student, you set your own syllabus. The examiner will judge the quality of your work based how well you address your own stated aims, not some preexisting expectation.
You decide what the focus is. State your purpose, stick to it, and don't worry about what you imagine the examiner might want.