There's so much misinformation in that article, I don't even know where to begin...
Since when were gravure scenes an original feature of the series? Since when were their butts and thighs realistically deforming before?
Also, do you have any idea what the "Soft Engine" actually is? It isn't a proper game engine that a game can run on, but the added features of subsurface scattering on the characters' skin, to make it look softer and warmer, and further improved physics of the breasts. It was named "Soft Engine" to sell those features, that you can find in many other current games as well, better to people who have no clue of the whole matter. It apparently worked. It's nothing special and the actual game engine DOA6 will now be running on will be able to run these features with ease. The question is only how pronounced does Team Ninja want it to be.