While it could be the completely new world continent out west, part of me thinks it could be Ivalice/Dalmasca. Urianger and Thancred were requested as neutral agents, which could be required for a peace treaty in say Dalmasca due to the war now being over. Erenville talking about a return home wouldn't be to an unknown continent, it would be to the Golmore Jungle. Finally, there was a lot of talk this patch about the concepts behind auracite and its creation and history. I don't think it would be too difficult for the team to have the Ivalice raids be required for MSQ since they already did that with Crystal Tower.