Since Iron Bull gave it quite the talk up I've always been interested in the Island of Seheron. The place seems to have a variety of major players (natives, Qunari, Tevinter, Tal-Vashoth). If the player were say a native guerilla fighter you could still have that cultural association and connection with Tevinter but still be an outsider of sorts. And this could be extended with meaningful race options as well, with the island's Tal Vashoth.
Ideally, I'd quite like the next game to be naval themed, visiting port towns from all countries in the north. Would fit with race options as well, unlike the Inquisition as a band of pirates are more likely to follow a dwarf or a Qunari because he's a tough son of a gun whereas a Qunari leading a chantry organization always seemed a little questionable to me.