IMO they are hinting at more people being able to fit in an alliance.
Let's be honest - does anyone kill Vrtra, Tiamat, or Jormungand -without- using more than 18 people? This system has been broken for a long time, and the fact that they are adding mobs like jailer of love and absolute virtue that are even hard to beat with 60+ people only lends more evidence to support the theory that they are planning to increase alliance size.
So, mark me down for increased alliance size.
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