Oh is that what you call adventure mode? The event system, wich is pretty much like the rare mob system we have on live? Surely that is mostly coded already.
They better stagger out the raids again, so i totally disagree with you. You will have to no-life if they release the raids at launch, and i really don't want that. The new Challenge modes and raids have to be staggered to give heroics some time in the sun. Otherwise everyone will just skip them.
As for the established base, i could agree but we know that isn't the reality. Otherwise classes wouldn't be getting dumbed down.
They want to atract a new audience and the movie is the best way to do that. I am 100% sure that the pre-patch will be in the heels of the movie and the expansion soon after. Worst case scenario i can see this delayed till august for the expansion itself, but legion in some form will for sure drop in the heels of the movie.