Strictly going by what's in the announcement trailers of each expansion this one seems a little light, but that certainly doesn't mean it's going to be bad or uninspired.
Cataclysm
Goblins and Worgen
Flying In Azeroth
New Race/Class Combos
World Redone
Archaeology
Guild Leveling (Defunct)
Path of the Titans
Mists
Pandaren
Monk
Challenge Mode Dungeons
Scenarios
Pet Battles
WoD
Garrison
Model Update
Legion
New Honor System
Artifact Weapons
Class Halls (Built from garrisons system)
Demon Hunter
Battle For Azeroth
Island Expeditions (Built from scenarios system)
Warfronts
Allied Races
A lot of the features introduced in every expansion are 'fluff', but keep in mind that there's always a lot more to an expansion when it's actually in the hands of the players. Also keep in mind that neither world quests or mythic + were announced during the initial gamescom reveal and they were very tight lipped about everything besides their key announced features. I think Battle for Azeroth is building on something that they think already works and trying to make a better experience overall and that's not a bad thing. Basically, if it's not broke don't fix it. My only real gripe is they didn't show or talk about more about spec redesign. However, there were some changes seen on the stage floor so that gives me some hope.