The Forsaken get lots of in-game love. So do goblins. Humans and night elves are all over the place. But what about Worgen? I love the starting zone of the worgen. It's dark and exciting and chock full of story. Then your worgen character is dumped unceremoniously on the shores of Teldrassil and told, "Hey, your people are in Darnassus. Of you go!" End of story. Well, not quite. You can get the whole story about the invasion of Gilneas if you complete the Silverpine Forest quests, but you can only do that as Horde.
Genn Greymane is a good character and the worgen have a fascinating origin story. But I want to see more and I don't want to have to go outside of the game or play another faction to get it. My second choice is draenei. Though you do get to see another draenei faction prominently in Outland, you otherwise don't see anything having to do with them outside of their starting zone. My third choice is the Forsaken. Yes, they already get a lot of in-game attention, but I wouldn't mind seeing even more.
Speaking for myself only, I have a Horde bias. But part of the reason why is that the factions are more fleshed out in-game on the Horde side.
What about you? Which playable faction would you like to see get more in-game love? Blog about it and link to your post in the comments. Or, if you don't have a WoW-related blog, leave your response in the comments.