First I would like to say that I love the direction that development has been going with the application.
With that said however, the ability to create sub-stacks (stacks within stacks) has been wanted by many users for YEARS!
I don't understand why this feature is either ignored or not created.
This is not an unreasonable request.
Whether stacks are logical or not does not matter to the end user.
For the organization of my content I need to have this feature.
I hope you consider creating this feature soon.