as a professional player with a highly informative and sought after opinion. It is my view that Legion peaked at Suramar campaign in terms of story telling. the rest was just cookie cutter.
In order for BfA to fall into the trap of standard go do this and help this person etc etc, it will require an actual proggressive campaign that has subs wanting to know what happens excited for the next week when a new time gated chapter of the campaign will open.