Preservationists are expected to battle a controversial development proposal for St. Vincent's Hospital Manhattan, fearing that New York City will sanction the destruction of nine buildings in a historic district to allow the construction of two enormous towers. Opponents say the towers would blight their low-rise neighborhood and undermine the value of landmark protection throughout the city. St. Vincent representatives say the project is necessary to reach the hospital's goal of providing a top-level trauma center and advanced teaching hospital to serve more than a million people.