One of the annoy parts of building a warehouse is building the staging database, its an important first step. The staging database is replica of the source systems. BIML can provide away to accelerate this process, however its not perfect. BIML is designed to create SSIS packages – and it does this very, very, well. SQL database objects, not so well. SSDT does this well.
The first step in the designing a warehouse is discovery, Azure Data Catalog is an excellent tool for doing the discovery, it allows you to connect to a wide array of data source types and gather the meta data that can be used to build the staging database.
My feature request is to add support for Azure Data Catalog to SSDT. In a nutshell add a item to this menu list