I've been thinking. What if they give us horizontal progression. Hear me out. WoW: Rebirth, after the battle with the Jailer we are sent back to Azeroth to be Reborn. FROM level 1.
On the theme of cycles we get a new way to play the game. A prestige type system where you level from 1-60 again but on a changed azeroth. You can choose to do this upto 10 times every time acquiring +1 all stats and a cosmetic upgrade of a character plate (think elite and rare elite). Every subsequent "prestige" level you increase requires more exp than the last. Culminating with a title and mount at the end. So we don't get an expansion where you get 10 levels and done but instead an on theme unrestricted system that allows people to play how they want. Also allowing for more use of the older zones and bringing people back into the WORLD of warcraft and not just the CITY SITTERS of warcraft.
Just a thought. Let me know what you think.