^There's supposed to be about 12 characters on each side, and the fighting system is obviously a bit the same but different. Plus they have to add iconic characters, it's pretty obvious that the vast majority of people don't know the difference between Marvel and DC characters and it makes sense to have the ones most well known in there.
What's so great about Soul Calibur? I'm not convinced about buying it until I see it first hand and that game hits $30. Only thing I want is the art book it comes with if you purchase the LE one but it's not even worth it.
I was skeptical about MK vs DC and thought it was a joke at first but it doesn't look as bad to me anymore. At least MK is going back to it's 2D side scrolling fighting system. I mean the latest MK games were pretty bad but I'm at least interested in seeing how it'll turn out.