Considering not that many people actually completed the mage tower when it was current content says a lot. (Someone posted a statistic in another one of these threads that said 18%)
Class design, scaling problems, useless legendaries, no artifacts. Numerous factors play a role in why it’s not the same and never will be.
Even if you could add some of those back or just tune the numbers it would still be easier with modern tool kits.
Players should just focus on getting the new challenge content done when it comes out. There is little doubt in my mind that Shadowlands will have more challenge content.
Even if they did go back on their promise and reopen all past challenge modes there is a good chance, there is a good chance a good majority of people wouldn’t complete it. However, I am sure more then 18% would because it would simply be easier by design.