Ah, sub docks requested again, I don't know if Jeff (OD Dev.) has any plans for this but I do know OD Plus already has this, it is called a tabbed dock. One dock, multiple tabs for different items.
A tabbed dock is not the same as a sub-dock or the ability to open another dock from the list by clicking on a dock icon.
Tabbed docks are not to everyones liking (inc me) as you cant have a.) magnify b.) 3d backgrounds and c.) the ability to completely hide it off screen.
Stacks and sub-dock in my opinion would be a real winner and be the main reason for me to move from Winstep (Nexus) dock.