Batman Arkham City DLC Teaser Shown

Rocksteady is teasing some DLC for Batman Arkham City with a new image shown off through twitter today. The image doesn't show much, but most people are figuring the image is Harley Quinn with a sledgehammer because the boots in the image look identical to the ones she wears in the game. Earlier this month a list of trophies for the planned DLC leaked and indicated that at least some of the DLC for Batman Arkham City will be single player story related. As to what types of story related missions the DLC will include is still unknown at this time. Hopefully we will here more in the near future; I would venture to guess that the DLC may be timed to be released somewhere around the time a certain Dark Knight Rises movie is scheduled to hit theaters. But that is just a guess I could totally be off, but it would make sense to drum up support for your DLC to be released at or near the same time one of the biggest Batman movies ever is going to be released in theaters. What would you like to see included in the DLC missions, is there any character left in the Batman villain that you would like to see included in the Arkham City DLC?