Renaming devices is a very very cool feature that is undiscoverable right now; I stumbled upon it completely by accident by right-clicking on a sink's "Profile" combobox, where a "Rename" popup menu appeared... which makes no sense given that I was not right-clicking on the sink/source name label, but on the profile combobox widget.
I believe it would be a thousand times easier to discover and use if there was a button for renaming, besides the existing buttons for "Mute", "Lock channels" and "Set as fallback".
Actually, the even nicer alternative would be to kill the rename dialog and popup menu for renaming, and just replace the sink/source label widgets with editable GTK Entry widgets. When "module-device-manager" is not loaded, that GtkEntry could be set to insensitive state with a tooltip containing the explanatory text regarding the need to load that module for the feature to be available.
The text entry widget might make it too easy to screw up. I don't know if we have a click-to-edit type button widget, but something like that might work, or maybe have it as a non-editable text entry with a little edit pencil icon to explicitly start editing.
That said, I'm not able actually see the rename context menu at all in Fedora 23. Anyone else seeing this problem?
nm the last, saw your comment about needing to right click on the combobox.
*** Bug 93487 has been marked as a duplicate of this bug. ***