Are there strict objectives to follow in an English essay?

Most of the time, English encourages students to be expressive and nuanced in the way they write. For A-Level, more so than GCSE, there are certain requirements put forth by different exam boards. Edexcel, for example, could outline literary context as a focus for one essay, and then in another the analysis of literary form is prioritised. But these factors and requirements should not be seen as restrictive. Yes, there are usually objectives to follow in an essay, but these are only coordinated so as to give students a wider skill-set in English, with all manners of a text being explored and learnt.