One of the only logical ways I can see the dispute of Mer over Man would be set aside is if a full scale invasion were to be had on Tamriel by the snake people from Akivir. This foreign threat could put all of Tamriel in danger forcing the high elves to put some bigotry to rest. As far as a setting goes Argoina would make a lot of sense. It being on the east coast of Tamriel and the fact that it has yet have it's own chapter in TES games. Along with the powerful Tsaesci invaders it could bring in some new faces and races such as the Tango mo (Monkey People) and Ka'Po'Tun. These other races could be great allies or enemies in the defense for our beautiful home of Tamriel.