The template function tpl_userinfo() outputs "Logged in as: <full name>". I don't see the point of displaying the user's full name, rather than the user name. Especially when the descriptive text states "Logged in as". I'm not logged in as my full name, I'm logged in as my user name.
As a supportive argument: with the default template, you have the "Last modified" text showing one name, and the "Logged in as" showing a different name (assuming the current logged in user is the one that modified the current document).
Additionally, I have my installation setup to use @USER@ for part of their signature. So, it would be useful to have the "logged in as" match up with the signature for easy cross reference as well.
I don't see why @USER@ shouldn't be changed by default for logged in as, but lacking that, making it a configuration option to use @USER@ or @NAME@ would be acceptable as well.