The Collections extra is an excellent way to organize your resources, much like Articles organizes its resources, hiding them from the Tree and providing a grid for adding and editing resources in the Collection's resource.
Since a Collection's resources are managed from within the Collection's resource, there is opportunity for even better control of user access to the Manager. A simple HTML-type Dashboard Widget can be created with nothing more than a link:
<a href="[[++manager_url]]?a=resource/update&id=5">Cute Kitty Blog</a>
Add the widget to the dashboard, and your blog editors don't even need to view the Tree at all!
If you have several Collections, and several different groups to manage them, Dashboard Widgets can also be PHP code, or link to a snippet. That PHP code can output only the links appropriate for the user's group.
Create a custom Dashboard for your editors with only the widgets they will need to see when they log in for a really customized user interface.