If they EVER touch Akavir, the series will go down the drain. If they even place the game there, there may as well be plasma guns, VATS, spartans from halo, barney, spongebob, and people from Fable dancing around and singing. The series would go the same place.
Why? You might as well say taking the game to Black Marsh would ruin the series - it is as mysterious as Akavir, too! Or Valenwood, or Elswyer - or even everyone's oh-so-precious Skyrim. Just because it was mysterious in the past doesn't mean there can't be more mysteries in other places. Plus, Akavir is probably as diverse and large as Tamriel. If the game does go there, it might only be a portion of the entire place, not unlike how Vvardenfell is but a small part of Tamriel as a whole.
I, for one, wouldn't mind some different races, architecture, philosophy, and interpretations about the Aedra, Daedra, and other forces that make up the TES universe. How do they view Tamriel and the Septims? How do they perceive the Daedra? What's their take on the creation of Nirn, Lorkhan, and the Towers? Why have they stopped interacting with Tamriel? What mysteries do
they have?