It’s like none of you read past the section where they took a massive dump on a majority of their player base below max WM level!
“Additionally, each time a player gets an Expertise bump, a level up banner will appear showing their new Expertise Level.” Straight from the mouth of the Devs themselves!! Who cares if your average gear score tumbles from 578 to 530 on gear you’ve already earned? It’s just a “temporary reduction in power” no biggie, just like the Devs said! But we get a BANNER now every time we level up our expertise? How wonderful is that?! 
I can’t wait for the sense of pride and accomplishment we’ll feel everytime we see that banner pop up! “WOAH! My great axe expertise is now 548!! Only 52 levels to go and I’ll be as powerful as I was three months ago!”