Originally developed with the Legion Timewalking Bonus event, feedback from players led them to decide that a personal skill challenge that's only available once in a while for a short time doesn't really fit. Starting the week of March 29th, the Mage Tower will be available at any time for you to access. It’s no longer tied to Legion Timewalking and will be another way for you to take on a challenge in World of Warcraft.
When you take on this challenge you won't get benefits from legendary items or anything that is expansion specific like Covenant abilities. So the challenge will be up to you without those extra bonuses. And you will be able to earn rewards for each challenge you defeat, and if you complete all seven you'll be able to score an achievement, "A Tour of Towers” and the Soaring Spelltome mount.
Both of these accomplishments are going to be there for the claiming by anyone who gives all of the challenges a shot. Yet now there won’t be a temporary time pressure adding a layer of an outside ticking clock to the whole experience.
Since the release of Eternity’s End, we’re in the time where Shadowlands’ story has officially wrapped, and new challenges are ahead when the next expansion is announced in April. Changes like making the Mage Tower a permanent addition are some smaller things that do really add to options. Blizzard has been making changes to help more players have a shot at appropriate gear, Legendaries (including through new systems) and this should fit among those changes.