Religious Worker Visa Improvement Act This bill amends the Immigration and Nationality Act to prohibit a consular officer from issuing a nonimmigrant R-visa (for a religious worker and accompanying or joining spouse or child), and the Department of Homeland Security (DHS) from granting such status, to an alien until DHS has approved a petition filed on the alien's behalf. An eligible petitioner may file a blanket petition, in lieu of individual petitions, on behalf of aliens meeting specified requirements for blanket petition inclusion. DHS may only include in approval of a blanket petition missionary service locations for which DHS has previously conducted a site inspection in connection with an individual petition for a religious worker. A petitioner may file a petition at any time to amend the list of previously authorized missionary service locations.