When working with large flows, I like to organize them into pieces with zones and (many) tags. Its very tedious to select all tags when I want to zoom out and get a big picture to see how difference pieces I categorize with tags fit into the flow. Likewise, when I have many tags its sometimes difficult to find what I am looking for.
A few features that would improve the user experience
"Select all" to enable all tags
Keep count of tagged objects
See attached picture for view box I am referencing