The only level I ever want to see make it into every MK game is the living forest.
Otherwise any other area just doesn't make sense story wise, though why should that stop them? It's a fighting game first narrative driven game fifth.
I would say the Wastelands of Outworld but MK 2011 killed my interests in Outworld and it did so mainly by it’s portrayal of the “Wastelands”. It reduced the stage to a stormy day at the beach in Outworld as apposed to giving us a look at this other world where the skies were purple at night, the rivers were dead and red, and the landscape was covered in rigid shale mountains.