#2 Japan
The emergence and subsequent dominance of New Japan Pro Wrestling has reduced the WWE's presence in Japan. The WWE has tried to stem this tide by getting Japanese superstars such as Shinsuke Nakamura and Asuka, as well as giving them a big push once on the main roster, but this has not been enough.
Shinsuke is the current United States Champion, although he has been absent from two successive pay-per-views, and Asuka seems poised to become part of the inaugural WWE Women's Tag Team champions.
If Asuka and Shinsuke go back home victorious, it might finally increase WWE's Japanese viewership. Another reason why Japan would be a good bet is that it is the home of six-star matches.
The WWE might finally get that elusive six-star match if their superstars land in Japan and absorb some of that magic. A WWE event in Japan may also influence some NJPW stars to move over to the US.