I love Tableau Prep, but need a way to create curated data sources that include calculations that aggregate on the fly. For instance, say I want to calculate a no-show rate on a yearly basis and then drill down to quarterly and monthly, etc. I can't pre-aggregate this calculation in Prep, but need it to calculate in my viz. If I publish my flow as a data source, I would have to recreate this calculation every time I connect to the data source. This becomes problematic as the number of calculations, connected reports, and users increases.
It would be nice to be able to publish a data source from Desktop that takes a published flow as an input. Or, add functionality to the Output step in Prep that allows for adding aggregation calculations that aren't actual aggregations.
I realize that I can export an extract from Prep and then publish my data source from Desktop, but this seems like an extra unnecessary step. Plus, when Tableau eventually lets you schedule flow refreshes on Server, this will become essential.