There are two distinct SE's. The Piedmont (clay soil) and the littoral areas (sandy soil), which includes all of Florida.
Ross is still the dominant style in the Piedmont. He may not have overseen the construction of many of his courses there, but he is still very much with us. The Maples, Byrd, Cobb, even Wilson/Lee took a lot from Ross when they worked in clay soils.
In fact, I think P'hurst, East Lake and Seminole were easily the most influencial courses in the region. (Much more influencial than ANGC.)
Our very own Mike Young works in the Ross tradition and has done over 20 courses in GA, and lots in Miss and LA.
As for the coastal regions, I'll go with Pete Dye. Harbor Town changed everything. The Golden Agers at Sea Island or Ponte Vedra didn't have anywhere near as much influence.
Bob