The first paid expansion date was not a promise, it was an estimate, just like the retail release date.
They ended up (from memory) releasing 9 months after estimated release date and I think we all agree, it was really still released earlier than it should have been. Right until the last few days of gamma, people were still saying, 'well they are obviously saving a lot of surprises for release'
Until we get an official answer, I'm assuming that we should at LEAST double the original estimate, maybe a lot more....