All the changes in Karazhan aren't a coincedence because in WoD this tower will lead us to... Draenor. I've watched the Blizzcon Art Panel today and I've noticed this:
Look to the left of Tanaan Jungle - "The Chronal Spire (entry way to Draenor)" - If this is the Dark Portal v2.0 for WoD then what building is it on Azeroth?
Answer is simple. Karazhan.
EDIT: This image isn't fake. Play this video from 25:19.