Our typical workflow consists of dedicated report writers creating reports in the Desktop app. At the same time I'm working on improving the Data Model which consists mostly of editing M scripts in ...
If PBIDesktop had a "developer" mode, I imagine it would split out the files within the pbix file (it is just a ZIP file with a pbix extension), and it could support source control providers and multiple concurrent developers. I can see the data model being one unit of development, and each report a separate file, as mentioned. Team development support, as well as command line options to generate templates, set parameters, create models from templates, and publish models to app.powerbi.com (or SSRS when that comes) would make Power BI a great tool for agile analytics.
