I've done quite a few BI/DWH projects and what I found is that the best approach is to begin from deep prototyping done by data analysts and ETL developers together. It may all start with just a few spreadsheets and a simple dashboard. After many iterations and a lot of brainstorming it grows into a rather developed working prototype that the both sides have equally contributed to. Then the prototype is productionized by the engineers using standard ETL/whatever tools. So everybody gets the credit, and everybody is motivated. This experience made me create EasyMorph [1] -- a tool for quick ETL prototyping and brainstorming. It's like Excel but for tables, and it's equally suitable for data scientists and developers.

[1] http://easymorph.com