The whole oppressive and hopeless setting, where all have to fight to survive. An untraditional fantasy setting that flips it all around, ruled by mighty sorcerer-kings who the players actually have a chance of becoming.
A place where everything is tested as a survival tool.
Basically the dystopic feeling of the original box.
I do not however particularly like the how-it-came-to-pass much however. I would have preferred if that stayed as unknown, especially we are all descendants of halflings.
That and the powers-that-be killing off all the dragon-kings from the getgo. Why write them up only to kill them the first chance writers get in the fiction.
I haven't read City-State of Tyr yet so I don't know whether I even will bring that change around in my third incarnation of the settings.