You have picked a big topic and one that literary criticism has focused on increasingly in recent years. One suggestion that you might like to investigate further is how migration impacts identity. This is something that, due to the way that globalisation has resulted in increasing numbers of individuals moving around the world, we are constantly aware of in our multi-cultural world today.
Whatever their motive for moving to a different country, immigrants are an excellent example of what we know as a hybrid identity in the way that they clearly bring elements of their original culture and home with them to their new country, and, through a series of acts of compromise or defiance, construct their own hybrid or mixed identities based on the extent to which they embrace the new culture of their new country or cling on to the ways of their former culture. There are obviously some extremes to point out, such as the way that often immigrants coming from one country will group together in a kind of ghetto in a new city and will have shops and places of worship that enable them to continue following many of the cultural norms of their previous home. However, at the same time, the United States is a good example of a country that encourages immigrants to embrace a new American identity, and sees itself as the "melting pot" of different cultures and traditions. I think an analysis of migration and how this impacts identity would make a fascinating essay.