The characters are lore. The players are not. There is a clear distinction. We players can find out a lot more then the characters ever will. A player can go to Wowpedia to find out story and lore if they want to. A character can not. Did someone write you a book in order how to post on a forum? Were you required to read all of the chronicles before discussing lore?
The experience isn't shallow just because you are not told a bunch of stuff. Our characters and those they interact with are not omniscient. And it will never be poor story when you make a character not omniscient. You do get a little bit of lore about what is happening on the enemy islands. As alliance I learned that the snakes were trying to take Vol'dun, The blood trolls were trying to take Naz'mir and were involved with G'hun. The only story that is a mystery for Alliance is Zul'dazar but you learn about the zone and some threats.
I don't get why you think it would be better story to know a bunch of details when you are establishing outposts as part of the War Campaign. Yet you expect everyone to be a psychic and know all of these details when they haven't even established a foothold in the zones yet. But you are right terrible story that our characters are not know it alls.