I'll move this over to the Site + Forum Help board, as you are seeking answers regarding your username change and the registration. The username change is something new we added, but we wanted to create something to help give people a chance to modify their names, as that was a large part of old-timers of the game wanting new accounts. The Registration has been adapted to open every 12 hours, so it is relatively less randomized than previously; however, we have been experiencing some issues with it, lately, but we're trying to look into fixing it. Hopefully we can get it running back to normal soon, so that you can create new accounts, if you desire.~
Locking this, since I believe your question have been answered. c: Best of luck to you!