I think the enviromens on DOA 2 are more complex (in geometry) than the PS2 Version of VF 4. So i don't See The VF4 backgrounds outta DC reach. But if they are, may be replacing some 3D elements with high res sprites could do the trick..
Soul Calibur characters have less geometry, but they are ahead on animation (TTT uses Tekken 3 Motion capture). Plus, in SC facial animation, hair appereance and Motion, muscles movement, breathing simulation ( sophitia's stage you can see that) are better than in TTT. The artistic direction and global ilumination are better in SC too ( or seem to be at least), and that helps to give characters a better look.
The only think I can agree on about SC is the gameplay animation