Provide an API for Power BI Desktop that allows developers to create their own data sources. It's literally the very first feature I went looking for in Power BI. If you had such a feature, you wouldn't have to do all of the work yourselves for individual data source requests (of which there are quite a few already under review). My personal interest is to create a PowerShell data source , so that PowerShell can be used as glue to open Power BI up to many other data sources (including REST, which was one of the requests). Being able to push data into Power BI via PowerShell is one need (already satisfied with the PowerBIPS module), but there is also a need to be able to pull and refresh PowerShell data using a gateway without having to deal with intermediate csv files on disk.