MMOs are literally nothing but grinds and speed bumps. They're meant to be time sinks that you put months into. The funny thing about WoW is that it has never been anywhere near as grindy as a lot of other MMOs.
Also Twisting Corridors is, in Blizzards own words, meant as the "Challenge Wing" of Torghast, if it's as challenging as mage towers then your average player may never finish it even with full gear.
https://us.forums.blizzard.com/en/wo...owlands/638371
"Speaking of Twisting Corridors, as we finalize tuning, Twisting Corridors should come into its own as the “Challenge Mode” wing of Torghast, offering eighteen-floor runs at a higher level of difficulty than the rest of Torghast, with cosmetic rewards for clearing certain thresholds."
Of course, calling it challenging means next to nothing, until final tuning we have no idea how hard it will be, but apparently they don't intend it to be easy.