#4 Ireland
The Irish are known for being rowdy, and ironically enough, they're known for producing world-class wrestling stars. If WWE decided to host a stadium event there, perhaps at Croke Park, then we have no doubt in our mind that it'd sell out fairly quickly. You'd have Irish fans from every corner of the country swarming to get tickets, in addition to many British and European fans who would make the short trip over.
Sheamus, Finn Balor & Becky Lynch all represent the best that the country has to offer, and you could even have the likes of Jordan Devlin & Finlay pop up on the night. It may not be as highly respected as a wrestling entity in comparison to other nations, but it certainly should be. After all, they've won quite a few world titles over the years.