They really have gotten completely lazy and are just recycling content, next expansion should be some return to Northrend with more old god Metzen corruption.
No new races.
Diablo artifact weapons.
New quest areas and shit to blast through on day 1 and never touch again
Class halls to go change specs once during the expansion
Illidan LOLOLOLOLOLOLOLOLOLOLOL
Demon hunter....seriously?
New Demon Hunter Hero Class
Level 100 to 110
New Continent : Broken Isles
New Honor System
Artifact Weapons (highly customizable)
Class Order Halls
Title : World of Warcraft : Legion
This is all I could hope for, hope they include Azshara at some point with the Old Gods under the Broken Isles wanting to meddle with the Legion stuff again (like during War of the Ancients).
Looks like it's race restricted as well, only Smurfs and Blood Elves can be Demon Hunters. Rogue population will probably dwindle to nothing after this.