Regencies are not the same as historical novels set during the Regency period. They are shorter, generally with an emphasis on Regency society and dialogue over action and sex (although Mary Balogh and others have brought sexuality into the Regency.) It's safe to say that Regency romances owe as much to Georgette Heyer (one of SF author Lois McMaster Bujold's favorite writers) as they do to Jane Austen. However, today's Regency doesn't have to be a drawing room comedy or a romp. The Regency can be about angst-ridden characters, about heroes discovering the importance of family life, about heroines recovering from sexual abuse, bluestockings, and even about heroines forced to become prostitutes (Mary Balogh's The Secret Pearl). Many writers started out writing Regencies before turning to historicals romances.