As a new tank, here is my suggestion:
I would love to see Blizzard integrating M+ routes directly into the nameplates of mobs.
Imagine that at the start of a key you as a tank link a route to chat. Others simply click on it to import. Now, not only tank but a whole group sees which packs are going to be pulled together directly from the nameplates. Visuals could be very simple in form of a number or colorful shape next to nameplates of mobs you should pull together.
This feature would help new tanks so much. It is my biggest gripe with tanking - remembering 100s of specific pulls.
P.S. I know there is/was something similar - “Pull Assist” weak aura, which functionality is not optimal.