This year's nobel prize in economics was awarded to Thomas Shelling and Robert Aumann. This is a very powerful pair of game theorists. Interestingly enough, you can see that a lot of Schelling's most intriguing work is not very mathematical--although later on, other people provided mathy models of his ideas--and yet, he takes you from very reasonable premises to really counter-intuitive results. Aumamn's work, on the other side, is very mathematically sophisticated... and yet, full of philosophical implications. Which goes to show you that you can make valuable contributions in social science with or without mathematical sophistication... but you have to be just as smart as Schelling.