The only problem with that is that if they charge less to the customer, they can't offset that by cutting employee pay rates. Sure, they have a full hotel, but that means also maintaining a full staff. And they have to pay the staff the same as they did before, only on less income. If you maintain your pricing structure, you may end up with fewer rooms full, but you can adjust your seasonal / temp staff schedules to help offset that.
Plus ... if you charge lower prices, then the foreign visitors (who are already getting a deal because of exchange rates) are getting an even BETTER deal. Which is great for them, but from a Disney business standpoint, not as good of a decision. Because many of the foreign guests are fine with prices as they are now, as they are currently a bargain. The only way around it would be charge more to foreign guests than to domestic guests, and that would be a public relations nightmare!