Modernism is not a design concept, its the view that the Church must respond in its teachings to the findings of science, especially biology (evolutionary, sexual, developmental). If the Church claims natural law as its moral method, it actually must. The whole idea that doctrine can never change must be abandoned as hubris. Modern architecture, by the way, is garbage but how we design our Churches is not a doctrinal thing, its practice, and the GIRM takes care of most of it.