The Single-Button Assistant will be the next best thing for me and how I spend time with WoW.
As much as I love this game, I believe most classes require way too many keys to get a steady competitive rotation including on use trinkets where many of us have resorted to addons like hekili to keep up. WoW over my 18+ years of playing has become a mmo of meters which has turned me off from the fun altogether.
Perhaps looking over all classes and reducing button (skill) bloat would be the best thing right now next to this upcoming feature. For example, why my rogue or enh. sham requires 2x as much keys to press compared to Ret. Paladin or DH is crazy.
I believe this assistant feature will be one step closer to fully enjoying the game, fight mechanics, visuals, etc. At least for me, not focusing on a addon that is dead center of my screen while using peripheral vision for mechanics of the fight would be so awesome. I swear sometimes my head and eyes hurt after a while.