Well this is interesting.. that and the transfer page hasn't updated since 6/22 --

"We would like to notify our players that, in regards to the ongoing World transfer applications, the Masamune and Aegis Worlds are approaching the maximum number of applications allowed. Please be aware that we will stop accepting applications once a World maxes out and further transfers will not be possible."

From - [NA] Status of World Transfer Applications for Masamune and Aegis Worlds

Both are also at 3 stars, but they've posted no such notice for Balmung or Excalibur