I agree with the article as well.
I never played Fantasy, and I did like the setting, but it wasn't that much different than any other fantasy setting. Age of Sigmar is a unique universe, unlike anything else. I love how involved the Gods are in the setting, and how important magic is (and the nature of the realms are), in shaping the civilizations which live (or struggle to live) in them.
It's hard to compaire the two games as apples to apples, as Age of Sigmar is such a new setting. It's only been around for a couple of years, while Warhammer Fanasy had nearly 30 years to develop it's setting and narrative. Of course the setting of Fantasy was richer, it had more time to grow. But, that setting still exists in the past, so it's still something you can draw from in Age of Sigmar. You could have a civilization decended from folks who were rescued from the old world, or be inspired by thier ansestors in the world that was. A number of the more immortal characters, would still remeber the old world.
What I am most excited about, is that the creative team has no single established world they are stuck sticking too, so future releases could be, really, anything. Kharadron Overlords would not have been a faction that would have existed in the old world, for example.
I agree the setting has a long way to match the old world, but that's to be expected. They've also only scratched the surface of what the realms have to offer. The only really big sources of 'world building' we have, were the Realmgate Wars books, Firestorm, the Season of Life campaign, and Malign Portants. These all only took place on the realms of Fire, Metal, Life and Death. The realms of Shadow and Light, have not even been visited at all yet, and we are only now learning about what happened to the Aelves.
I'm excited to see what GW has in store for the setting, and to see what new and excited factions and locations they have to come up with.
Additionally, the game is a lot of fun, and (in my opinion) better balanced than warhammer 40k