Problem/Motivation
we make several base fields to use just Entity field formatters and not special purpose field handlers in views. However, we have a lot of other field handlers in views that have more functionality than the corresponding field formatters.
Proposed resolution
Replace user_name with new field formatter
Remaining tasks
create patch
User interface changes
Entity fields will have more formatting options available, and they'll be consistent with what is available in Views.
API changes
None