As we can read on Kotaku, before Mortal Kombat VS DC another MK game was pitched, but it was never fully developed. You could say that Mortal Kombat 8 was released as MK VS DC, but the original concept for this new chapter of the MK saga was much different from what we got in the end:
Once again, we pestered Mr. Boon about the scrapped version of Mortal Kombat 8, once described by the long-term Midway dev as being heavily inspired by the look of Gears of War. While that grittier, darker version of MK didn’t make it far beyond the technology development stages — Boon told us there was little in the way of concept art for the grimier spin on the series — […]
In november 2009 an article at Game Set Watch revealed some concept arts that are assumed to be from this cancelled version of Mortal Kombat 8. It’s currently unknown how the gameplay would have evolved from the traditional fighting game, but if it would have followed this “new” style, it could have been something like “Gears of War” with more open arenas than the usual MK ones.