It looks as though the South of Sudan is going to vote to secede from the North- who will let it happen, which is nice for genocidal maniacs. This is a very good step in the right direction, like many countries in Africa all that links the country is a colonial history not a sense of nationhood. In fact nations in the European sense of the word that emerged in the 18th and 19th centuries don't really exist in Africa.
Instead there are a hodge podge of multi ethnic polities based on who colonised them a 150 years ago, in which the prime goal of any aspiring is to improve the standing of his people relative to the other ethnicities. This breeds corruption and racial hatred. In Sudan the racial differences are obvious because the North is Arab and the South black African but the differences between different black groups in Nigeria or Zimbabwe are just as real.
Creating function ethnic based states won't be possible everywhere but in cases where it is it should be encouraged regardless of the vested interests opposed to reform.