If you think Pesach is too difficult for a short essay, try thinking of a different subject, like Chanukah. But if you want to stick with Pesach, how about focusing just on the structure of the Haggadah? The Haggadah as it is today was developed over several centuries. There are sections from the Mishnaic and Talmudic eras that put a focus on the way things were during the Temple period with hopes of returning to that, and there are later sections, such as the song Chad Gadya which is commonly thought to represent Hashem saving the People of Israel from all of their historic enemies. And of course, there are the differences between the Haggadot of different Jewish communities.
