Travel costs are a legitimate concern but consider that if the location of the WC's moves to Europe, or Asia, or wherever a fair percentage of competitors will always get dinged. If the concern is fairness then we might as well move the **** thing to Antarctica and everyone can pay a few months' salary to go.
WC's is in Minnesota because FFG is in Minnesota. An added benefit is that Minneapolis is well connected to domestic and international air travel routes and the cost of room and board is relatively low.
If FFG were to look to move the WC's anywhere - I would have to say Vegas might be a good spot. Cheap rooms, cheap flights, lots of space, warm weather.