In the DRC, there is the East/West divide, but none of the distinct ethnic groups are a large enough share of the total population to provide the "Big Ethnic Bloc" fights that arise in Nigeria.
Perhaps there is a form of Federalism that can work in Nigeria once the income generated by crude oil wanes, but global Peak Oil will be working to expand crude oil revenues even after oil production volumes peak and then decline. I've been accused of being a Marxist, yet while Harpo's my favourite, it's Groucho I'm always quoting. Odd, that.