It makes no sense for a company to hype fake things for no reason. Overhype stuff? Yes. But giving bad info with the intent of disappointing people? That's not the case.
I will say that I agree about not holding your breath, but for different reasons. There ARE expansions planned for Epcot, DHS, and MK. They have budgets, concept arts and timertables. The problem lies in whether or not they actually come to fruition. What I've seen from them is cool (and some of it is original and not IP-based to boot!). But none of those things are confirmations. So no, they're not yanking people's chains. But yes, it's not worth getting excited over for now.