We have plans to be able to set the label or folder directly when importing from online resources: Add tags and folders when importing from Chrome extension
That could include that the extension remembers your last label in some way so that your imports all end up in one place.
We don’t have plans to add another layer of organization as you suggest though. I think with labels you can achieve most of the functionality you describe. For example if you select a label it shows like a tab on the top. If you search or filter it stays there so you basically get a separate view of your library.