I so wanted this plugin to work. Alas. It appears that with the latest update to WordPress 3.3.2, not only does this plugin fail to override the username restrictions, but all attempted new usernames are rejected with the error message, "Username must be at least 4 characters." This occurs whether attempting to add a new user at the Network Admin view or at a specific site view. If the plugin is deleted, normal (restrictive) add new user behavior returns.