Im happy to see you included Saids essay- though you may want to revisit to draw more from Saids discussion of Conrads racism and how this affects Conrads ability to comment on imperialism. 

Consider also my revision to the prompt. Achebe declares explicitly that a work which dehumanizes cannot be a great work or not. I think your discussion incorporating Saids essay can offer a unique, thoughtful perspective on this notion.