I think this kind of thing is pretty hard to do
1. You've got characters who only exist in a 2D world, that typically creates some difficulties as soon as you need to move them to 3D.
2. Their entire animated history exists in a super low framerate, something that doesn't translate very well to comfortable gameplay
3. You've got different characters, by different artists , animated by different animation studios all with thei own trademark looks.
It's not to say it wouldn't be impossible, but perhaps some early choices have made this even more pronounced. The natural looking textures and lighting on characters that only exist as animated cells does look pretty awful.
It's certainly hard to look at after seeing DBFighters
However,It does look like some of the mo-cap has been done using a Kinect.