What ever subject you choose may be dependant on your own personal views. It may also depend on who will read the essay and what knowledge they have. For example, I took one of my stories to a literary agent, the agent didn't have any prior knowledge of the subject, and unfortunately for me she got info from Wikipedia, which it was wrong. Point being if you want a good score [whatever] pick a topic that will be well recieved. You may well choose the feminism angle, but the person reading your essay may be against feminism.
A generalised theme would be easier to write about as there is more to write and yet can it be concluded, in two pages ?. Such as the feminism issue or the religious ramifications.
What is the reason for the essay ?, your ability to write an essay that is understandable ?, that your spelling and punctuation skills are correct.
If it is about your choice of subject then how about picking something different; the fanfics, the content of the forums, how the series is percieved today ?.
