Such development is at the heart of the unfolding story of Cataclysm. The Orc was sent by the new mistrustful warchief, Garrosh Hellscream, to spy on his so-called allies. In a cutscene shown in the second expansion, Wrath of the Lich King, a faction of Forsaken led by Grand Apothecary Putress fires poisonous gas on Alliance and Horde forces alike, decimating them. Hellscream is careful to prevent another Wrathgate scenario by denying his undead allies access to anything that can be used as a biological weapon. We are shown in Cataclysm that Hellscream is actively trying to stop such betrayals from occurring again and the player experiences that first hand through participating in this quest.
Storytelling like this shows many things. First, the events of the previous story told in Wrath have significance in the world; they are not just isolated quests or dungeons that have no bearing on the greater world. It also shows the fear and suspicion that the leadership of Garrosh Hellscream is engendering within the Horde. Not only has he cast the Trolls out of Orgrimmar, but he is openly mistrustful of the Undead as well. I'm not sure how the story of the Horde will unfold, but I love seeing seeds like this planted throughout all of the content. A newcomer to the game will be entertained by the quests, and veteran players will enjoy learning how relationships have changed.
Originally, the Alliance had a small presence in the Orc-lands of Kalimdor, but the humans are pressing forward in Cataclysm. South of Ratchet, a band of pirates under the command of Baron Longshore plowed the South Seas for booty, and a quest in early WoW sent you to cut off the brigand's head. But now in Cataclysm, the Alliance have taken control of the area. Horde players are asked to kill Alliance marines just as they used to kill pirates, but the military presence hammers home the point that there is still a war being crafted.
Baron Longshore isn't out of the picture though. He's been captured, and sneaking up to Longshore reveals that he has one more card up his sleeve. If the player chooses to break Longshore's chains, he reveals the location of the treasure that he stashed away before the Alliance captured him. I'm not going to give away what happens next beyond saying that you shouldn't trust a pirate, but once again, the brilliant references to ongoing stories enhance the game's storytelling.
These three quests in the Northern Barrens are only a handful of the stories that have gotten an update with the Cataclysm wrought by the great Deathwing's emergence. All over Azeroth, so many new and different stories are being told in World of Warcraft that in many ways it may feel like a different game. A lot can change for people in six years, but until the patch that shattered the world of Azeroth is installed on your computer, there was little indication that anything had changed for many characters in Blizzard's game. Now with Cataclysm, the designers at Blizzard have progressed the timeline throughout the whole world in order to tell exciting new stories that will entertain both new and old players alike. It's made Azeroth feel a little bit more like a real, breathing place, instead of just a bunch of pixels.