I think a high rating doesn't make a manip 'better' (as many people out there seem to think), and it may make it more sexual, but that isn't the same as portraying emotions. In my opinion, the small gestures tell so much more than any sex-scene ever could. Many people confuse love with passion, I guess...

PS: I don't actually do this stuff consciously, it's more instinct. I don't plan my manips, I just see the original pictures and I get an idea of what I want the manip to look like and the small stuff develops while I work on it. It's rather hazardous, but I'm glad I seem to get the emotions across I associate with the manips in my mind. ^^