Although Victor Hugo was a talented playwright, it is really his political activism that mattered. He could even be credited with the abolition of the death penalty in Switzerland.
Although Hume's classic Treatise on Human Nature is a key work of political philosophy to come out of the Scottish Enlightenment, Hume's forgotten masterpiece Of the Standard of Taste, in which he argues that judging art is not arbitrary, is probably the most important work in aesthetics before Kant.
Although Yale has a good law school, Yale itself can feel more like a retirement community for geniuses than a stimulating university: The great Yale faculty members get tenure there decades after doing their brilliant work elsewhere.