I've been wondering about the username instead of name field thing too. This is especially relevant to me as most of what I do is RPing, and being in some rather large games with high character turnover, it's nice to be able to identify characters I don't immediately recognize from the icon/username without having to click all the way to their journal profile. That, and having the name field in the hover text is useful for those people who like to change their usernames periodically...