It would be great to be able to define username and full name blacklists via the Administration console. This would especially be great for Confluence installations with public signup enabled. For example, taking Atlassian's own Confluence - there is nothing to prevent users from signing up with a username such as "atlassian", or "atlassian.sales", or "atlassian.staff", etc (not to mention rude words). Similarly with full names - there is nothing to prevent a user from changing their name to "Atlassian Staff" and such.

As far as I can tell, the only ways that the problem can currently be avoided for usernames are either disabling public signup, or painstakingly creating users with disallowed usernames (not ideal as they would count toward licenses - also a problem if a 'disallowed' username authors content before it is picked up).

For full names the problem is even worse, as anybody can change their name at any time and there is nothing preventing multiple people from choosing the same name. For example, 20 people could all change their full name to "Atlassian Support" regardless of whether they work at the company or not.

The blacklist should be ignored for administrators, perhaps with a warning/confirmation screen if their choice of username/full name is picked up by the blacklist.