You’ll be too busy working on your Legendary Cloak in the Horrific Visions to worry about a Mage Tower. You can do the visions solo or in a group. At least that is their thinking.
If 8.3, doesn’t launch until 2020 (as just announced), you’ll have 6-7 months before pre-patch to finish it. Doesn’t really leave much time in the cycle for a big feature release with solo content.