It's possible we get no new countries, but it's also possible we get two.
On top of Brazil, Spain is a big contender, mostly because of the animated movie "Gigantic" coming out early next year which takes place in Spain. WDI has high hopes for the film's success, as the more successful it is, the more likely a pavilion is to happen.
Martin mentioned it's "highly probably" that within the next 5 years a country is added. He stated higher ups have finally come to terms with the park needing help and poor guest surveys have only made the need more evident.
Oh, and apparently Rat is greenlit.