It is not clear to me what the point of the Username vs Fullname.
There is an option to have "unique usernames" however if usernames are enabled they are not displayed anywhere - fullname is still the profile identifier etc.
Likewise the mandatory use of fullname is not good for sites that want their members to be anonymous.
What I am proposing is two changes.
1) The ability for Admins to have members use Username OR Fullname i.e. fullname is not mandatory.
2) IF Username is configured / selected as the primary (unique) identifier then Username replaces Fullname labels on Profile , Comments, Posts, etc
6
votesUsernames and Full Names