you cant rely on players to do the work creating the world. If you have taken the time to provide options, define races, etc. you really do need to go the rest of the way. Your the DM. You create this world. The players ask for changes, variances and other things. But you make the world. Despite what people think. Players want something structured to go into. Because if its structured it shows the DM has a firm idea of what he wants. And that is a sign that maybe this will last and not just waste my time with an application that will go nowhere. 
and what do you mean 'A politics" just tell us how each nation is privately run. Council of elders, do some have kings, emperor's chairmen? military states? I don't know. Have some fun with it.