"Handling the metadata was the really big challenge for our DW. 250 trials, each with 30-40 distinct tables, adding a new trial a week, I had to develop a dynamic ETL tool that was fed by a metadata repository. Finally, the metadata of an individual trial could and would sometimes change in the middle of a trial."

Steven, I think you are correct that the first versions of the data warehouse model ignored metadata almost completely. In his article, "Information Management: DW 2.0 - Architecture for the Next Generation of Data Warehousing" Bill Inmon addresses this problem in the his latest version of data warehousing, what he calls "DW 2.0". In it he states: "Metadata is the glue that holds the data together over its different states. Amazingly, the first generation of data warehousing omitted metadata as part of the infrastructure."

I have to agree that without sufficient (and automated) metadata together with proper release mechanisms, schema maintenance can and will become a full time occupation.