Anne Hathaway, Stanley Tucci, Meryl Streep, and Emily Blunt at the world premiere of "The Devil Wears Prada 2." Mike Coppola/Getty Images for 20th Century Studios "The Devil Wears Prada 2" is earning positive reviews and is poised to be a box-office hit. Set 20 years after 2006's "The Devil Wears Prada," the movie could be considered a legacy sequel. A legacy sequel takes many years to be made and often stars beloved original characters. As you might've heard, nostalgia is a powerful thing....