Your implementation of dynamic lighting that matches the background environment makes the overall image look noticeably darker. In particular, the areas that are supposed to be the visual focal point—such as the genitals—are usually located near the bottom of the image, where there's naturally less light, causing them to lose emphasis.
I don't really like that approach. The CGs in the game are already fairly small, so I don't think it's necessary to make the characters blend so seamlessly into the background. I think it's more important to preserve the scene's visual impact than to pursue perfectly realistic lighting.