I certainly think you are on the right track with this theme in this particular work. I would focus on analysis of Okonkwo in the first part of the book and how he views the Ibo and how the Ibo, itself, functions away from the corrupting influence of the West. The social order that Okonkwo reveres before his exile is vastly different than the one he sees when he returns to it. I would then contrast this with the later sections of the book in terms of examining the change in the Ibo society and the perceptions of one another when the Europeans have entered this world, his world. Being able to analyze this change in terms of the West's presence in the village might help illuminate your thesis a bit more as it demonstrates how both notions of the cultural good collided and only one was able to generate success in this clash. Along these lines, I would focus on how the communitarian vision that is present at the start of the novel in Ibo life is something more isolated and more alienating once the European cultures enter the village. What was once traditional has been disrupted by modernity, and what passed for honor has been dramatically changed with the presence of the European culture in the presence of the traditional African one. Perhaps, emphasizing the religious nature of customs and change could assist in this process, as well. It was shown quite passionately in Achebe's work that Christianity was used to usurp traditional African spirituality, demonstrating how there was a complete clash of civilizations in the expression of the spiritual notion of the good.