It makes far more sense for them to have been set up as patch content from the start. We knew all the launch zones as soon as the expansion was revealed at Blizzcon, I doubt that it was already cut and all this marketing was already set in stone all the way back then.
They're probably just teasing them now rather than introducing them out of nowhere in 11.1 or 11.2. Seems like a good approach, since people are already looking forward to meeting them, and hopefully playing as them.