African input on the borders would have prevented some of the violent unrest.
Being Europeans drew the border lines, they did not understand tribal, ethnic, and religious differences between the native groups and this led to haphazard border lines.
Therefore, countries contained very different people who had been enemies before and/or during the colonial period. The feelings of resentment were allowed to resurface as groups fought for power power. This led to violent civil war and even genocide like in Rwanda. If the native groups would have been allowed to create their own borders, nation-states would have been created which would have led to unity and a more peaceful transition.