I think it's a great idea since I had considered wanting to change mine to something else.  However, it had me thinking.  There are a lot of users on here who change their fandoms like they change their clothes.  The rule stated you can't change it again for six months.  So let's say you wanted to have Barnabas-Collins-Fan.  If you suddenly lose interest in Dark Shadows, you better not have chosen a name like that.  You should pick something that you know you're going to want to have for a very long time, even longer than six months.  Since I've been a fan of TGMD for more than six months (try six years as far as the rediscovery goes ), it's safe for me to choose a name from that fandom.  Though, I'm still a fan of TMNT, I want to keep a portion of that fandom in my username as well.