Yes, I know we have a new raid finder wing, but I can't help but feel a bit focused on the upcoming patch.
Since Burning Crusade I believe introduced the world of Argus as a concept (I can't remember if those Argus Wake guys in Alterac Mountains existed already) we've more or less known only one geographical feature of the world from which the Eredar who would come to be known as the Draenei fled, and that was the capital city of Mac'aree.
Your adventures on Argus will begin in what is called at least for now "Argus Wastes," and this area will feel pretty familiar given the Legion's MO. There is some interesting new wildlife, and I think they get the feeling of a desolate, ruined, but at least somewhat still intact world in this area. Unlike, for example, Niskara, not everything is burned black with green flame, but it is still a place where there's almost no non-demonic life there.
After completing the first leg of the Argus quest chain, you'll eventually travel to Mac'aree. You can see the capital floating above the Argus Wastes in the skybox (cleverly, they tend to point you in the direction of Azeroth as you adventure across its new twin world, and you also see Mac'aree in the skybox.) Traveling to the capital, you'll be able to access a fragment of the city, the rest of which is drawn into the skybox behind, to really give you a sense of how enormous this place was.
And Mac'aree is broken, but not utterly ruined. And it certainly does not have the stereotypical Legion look. Mac'aree calls to mind much more the Warlords iteration of Shattrath, with the Draenei (well, Eredar) style of spire-like buildings. (In fact, I think they took assets created for Warlords and adjusted them only a bit to build up Mac'aree.) Far from Black and Green, Mac'aree is awash in golden grass with spots of purple vegetation and buildings of yellow, grey, and some blue. The impression this suggests is one of the city as the seat of a society that was once near-utopian. At least in the first few quests, the NPCs are largely ghost-like echoes of the ancient Eredar. You'll even go to the academy where Archimonde (and his teacher Thal'kiel) once studied and researched.
I really have to say that if you have any kind of roleplaying sensibilities and you play a Draenei character, Mac'aree perhaps even more than the Argus Wastes will feel like coming home.