There would be a new phase when something big would happen.
Alpha-->Beta (Merger with AE)
Beta-->Gamma (Robots, mutating weapons, enchantments, agility, Encumberance)
Gamma-->Delta (new classes)
Delta-->Omega (completely new weapon system and class system)
I feel like players would be angry if they just changed the phase name for the sake of changing it and for the symbolism. I think they would have to do something big before changing the phrase, for example remove the level system and legendary ranks (give achievements for compensation), give everyone a set amount of skill points and stats, and give them the ability to buy 3 extra skill points for varium.