I'd actually like to see multiple subcultures and settlements for the Atlanteans.
Momoa's poster, with it's Pacific Islander design for a traditionally Atlantic bound hero, and with its catch phrase of "Unite the Seven," gives me some hope for a disparate and scattered kingdom of Atlantis, one with cities and settlements throughout all seven seas, each hearkening a bit towards the surface world they are closest to, but still sharing a common language culture and ambiguous ethnicity. And I'd throw in a few more surface world friendly Atlanteans, along with a major civil war theme of the outlying and distant kingdoms against the centralized capital.
So, Xebel, with it's Bermuda Triangle location, would have a more Caribbean air and would be home to not only Mera, but also hybrid characters like Lorena, though she might be a candidate for being a hybrid with Hispanic ancestry as well.
Poseidonis, as the traditional capital, would be located in the Atlantic, and have a gilded age and imperial theme to it, with Orm and his father ruling there. This would also be the most advanced but stratified city in the kingdom, since it's held by a sorceress monarchy.
The Pacific colonies would share a strong connection to their Islander allies, with Arthur hailing from there, as well as sorcerously mutated beings, like Lagoon Boy and asking Shark.
I'd have an old Capitol in ruins located in the Mediterreanean, a frozen world ruled by the Dead King, and other such areas throughout.