There can not be a history in WoW because nothing ever changes. Sure, there are occasionally 1-time events. The opening of AQ 40, or the Scourge invasion, but honestly, these 1 time events aren't a history, they are just a 1-time thing that you either got to see or didn't. For the vast majority of players, there is no imapact they can have on the world at all. They've killed hundreds of thousands of radiated gnomes, but Gnomerangan will always be inhabited by more of them. They've slaughtered Illidan over and over and over, yet he'll pop right back up again after the next weekly reset.
I would say that the history of wow could be greatly improved if blizzard had implemented a feature in Caverns of Time (existing time travel in the game) to take the character to a future version of the game world based on completed quests. This way the players could see some real in game rewards other than the level and gear of their characters. In my opinion this would give the game a better sense of accomplishment for the casual gamers.
Truth is free, but information costs.