Yes, Disney is expensive. But if you move the competition from Disney, I'd bet the International competition goes down by over half. And that would be a huge blow to the whole "World Championship" idea of it. Plus you can't beat WDW with their entertainment, transportation, lodging, etc.
All that being said, yes I do think the Milkhouse is too small. My solution = give less bids.
There can never be growth by international teams if the venue stays at the Milk House unless of course you start bumping out us teams.