Thanks, this is pretty awesome. If you don't mind, I'd like to suggest two minor changes:
"External database" -> "3d party". Technically it can be a database, a service, a file, whatever.
I'd remove the arrow from "transform functions", just leaving the box there. Technically it interacts with nornir's inventory and it doesn't have any knowledge of the inventory plugin
Added diagram to docs describing plugins architecture to make it easier for people to comprehend the greatness of Nornir.