https://twitter.com/TESOnline/statuses/299912466933112832 from the TESOnline account, but I can't see the Akaviri having one visual appearance in the MMO and a distinct appearance in the "real" games.

Since TESO takes place mid-2E, the Akaviri invasion is long since defeated and even the Potentate is over. The Imperial invasion of Akavir doesn't happen until the 3E. I'm guessing (wildly!) that the Akaviri we see will be a remnant of a remnant living out their last days in Tamriel before assimilating into the local cultures. If the Akaviri races are really new beast races, then they might not be able to breed and disappear into legend. If they're human, then they could melt into the local population with their differences forgotten over the years.

Depending on the timing between TES6 and TESO's inevitable expansion, we could finally see some real answers to the Akaviri questions!