I don't think it's so much a matter that they don't want to open HoP, just that they're still waiting for the president to record his speech. That's my take on it anyway. Everyone thinks Disney is holding out on purpose, but from the quotes Disney has made on the subject, seems like they're waiting on him.
Personally, I'd just create a cut-and-paste speech using Routers or Associated Press recordings, but that's not the way they've done it in the past, and they probably don't want to upset anyone by not giving him the chance to record his own for the attraction.