Found an article on my news feed today about this. Apparently Bliz is finally listening to players.
https://us.forums.blizzard.com/en/wow/t/shadowlands-update-some-spells-no-longer-on-gcd/630189
UPDATE: This link is broken now and only shows a “404 page not found” error message. But if you google just “shadowlands-update-some-spells-no-longer-on-gcd” several threads will pop up for you.