Address usability when working at scale

It is clear to me in many aspects of the UI consideration has not been given for working at scale.

For example:

Our tag list has grown to several thousand entries and yet I can only prune the list one entry at a time.

Our product tree has over one thousand entries so assigning product access to users is really time consuming 

When editing filters for various views the list will show workflow attributes for every workflow in your instance (we have several) which is very confusing

There are many other examples.

I would like to see a rigorous review of the end to end user experience with an emphasis on enterprise scale operation and enterprise scale datasets.  This should be from a contributor perspective a product owner perspective and an account admin perspective. 

I see this as high priority because our use is growing rapidly and we are already at a scale where some aspects of the tool are becoming almost unusable.