I think its somewhat incorrect to say that all the characters look the same, whether its V4 or Genesis, as if it somehow defines the limits a character might have. To me it sort of like saying that Batman look the same whether you see him in a movie or a cartoon. The way he looks even with some minor changes to his suit is what defines him as Batman and makes it possible to spot him as a character. Its the same with V4 or Genesis, if you add slightly different textures and only minor changes to them, you can spot them just like batman. But V4 have more than enough polygons in her mesh, that you could make her look like a troll if you wanted and on top of that add normal maps and new textures, making it impossible to know that its based on her.