When it comes to Greater Washington philanthropy, Rosie Allen-Herring is a stalwart leader. In her four years as CEO of United Way of the National Capital Area, Allen-Herring has sought to run the local arm of the national nonprofit giant with business principles in mind. For the Mississippi native, that means a focus on financial stability (she balanced the organization’s more than $30 million budget in her first year) and transparency (this year, United Way NCA earned “platinum” status by…