The thing is, it's one thing to have a plot point, and using it, or else it's just world building information. Without the trailers and fanfests specifically telling us we'd be going to the First and become a warrior of darkness (the selling point of the expansion), we'd have no idea what ShB would be about, aside maybe fighting more Garleans...which....we spent all SB doing. If anything, it'd lead people to believe we're going to Garlemald instead.