Even though I personally don't think WWE will downsize anytime soon concerning the venue size, I think that as King502 stated above has a point in saying that Vancouver, BC deserves a Wrestlemania. By and large, when WWE comes to Canada, they goto cities such as Calgary, Toronto, Montreal, Winnipeg, etc but strangely have never held a PPV in Vancouver yet.
While we're on the subject of venues, I think that whenever WWE finally holds Wrestlemania on another continent, that using venues(which would usually be open-air venues) in places such as South Africa, Australia, Russia, Chile, France, Hungary, Greece, Spain, China, etc would be a great idea..Whenever WWE gets to holding more televised events in other countries, especially for PPVs (for example, Wrestlemania) just by WWE traveling and helping to promote the event throughout the country, that will in turn help to dramatically expand the WWE's fan base in whatever country WWE happens to be holding Wrestlemania in and it'll also leave the door open for WWE to hold more televised events in said country as well in the future.