If your essay requires a proposal, do not assume you can whip together something quickly and consider it complete. Chances are, if a professor is requesting an essay proposal at all (which means more work for them to do), they intend to actually pay attention to it. It may even have a grade value as part of the overall essay. You will likely be held to promises made in the proposal, so don't state that you'll do impossible things under the assumption that the professor will be impressed.