Honestly, most people don't take more than one vacation year, if even that. So, what is the incentive for that one vacation a year to go to the same place every time? Oh, yeah, to play Pokemon...but, what if, as Ness has stated, we actually move the event around? I'm not sure how that seems like a bad idea to ANYONE.
As for some places, I think Nats should try and stay somewhat centrally located and not get into any extremes (SoCal, NW, Florida, New England). Specific cities I would like to see Nats (in no particular order): Dallas, Chicago, St Louis, OKC, VEGAS!!! (I know, NOT kid friendly), Memphis, Denver. Wouldn't mind some centrally located East Coast areas, like NC, or just about anywhere in the Midwest, as long as it differs.
And, for Worlds, I think this has more potential. This can fall in those "extreme" areas (SoCal, NW, Florida, New England), except it has already been to most of those. So, hitting up some other large cities arcoss the US would be cool. As far as going international, it think it seem stupid to keep it here in the US, it is WORLDS!!! But, Ness is right, it certainly needs to be in an area where English speaking people can get around easily (ie, England). Now, that's not to say it can ONLY be in England, English is spoke in MANY countries around the world. But, the POP reps in that country would have to do a lot of work to ensure it is accessable for English. As far as going international, I think this should be on a set schedule, say, every 3-4 years, and should be decided on by a P!P committee that would have a selection process that is (for lack of a better comparison) similar to the Olympics selection committee. Also, I think the P!P should give away trips in the "inbetween" yearrs. As an example, maybe hold a few tournaments (or one) a year that has a small fee to enter with the prize being a paid trip to the international Worlds and/or give all Worlds winners another paid trip to the international worlds, meaning we could have the last 2-3 World champs get automatic invites to the international worlds.