I just asked this question, too. The role of Women could eb considered plagiarism considering that one of the greatest 50 EE's is on the Empowerment of Women in LoTR which could be rather similar to what you were planning.
I'm doing my EE on Tolkien's work in general. I'm going to analyze Quenya and Sindarin and how it impacted the work or something to that effect, I don't have my theme clearly set yet. However, I want to analyze the literature from a more linguistic aspect considering that it is what I want to major in, too. I think that nobody has done that before, but I have to check.
I thought I was being original, but then I checked and noticed that another million previous students thought that they were being original, too. xDD So, I suggest that you find something that nobody has done in LoTR, which is rather hard. I know my friend did The Faces of Evil in LoTR. Perhaps you can try doing another Tolkien work? The Hobbit, The Silmarillion?
I've decided to do Tolkien in general rather than focus on one work.
Anyhoo, good luck. Hope my insomniac rambling was of any help. =P