Four reasons ratings are tanking.
1) too predictable. In other sports, the favorite has a chance of losing. Not WWE. Maybe a champion losing in a non title match, creates some doubt, and interest.
2) only the "heels" have personality. With some exceptions. Do we need heels? Why can't all the wrestlers cheat a little now and then. No heels in NBA or NFL and they do just fine.
3) Too much change too quickly. After the 4 best women's tag teams met at Wrestlemania, 3 have never been seen again and the champs are losing to a new tag team every week. Why not build some rivalries? Seems to work in other sports.
4) more wrestling and fighting, and less acrobats. Especially acrobats with no personality. Even flying around the ring gets boring to watch after a while.
Otherwise, everything is great!