If you’re looking for the real logic behind it, its because the majority of the player base is dps. Every expac has to have a dps as a new class. Otherwise the majority of the player base wont have a new class to play for an expac.

Last expac was healer/dps, one before that tank/dps, and before that dps x2. Its cyclical. So we were “due” for another double dps expac. Obviously the devs and director are free to make whatever decision they want, but this is the logic yoshi/the devs have talked about on their quarterly chats. (To my understanding)