I think practicing softly is actually much more difficult than practicing hard. To practice softly and well takes a lot of skill. A couple months ago, I went to a seminar taught by Elliot Freeman, one of Steven Seagal's top students. He insisted that everyone practice full power, just at a speed that your partner can handle. I think it would take years of this kind of training to then be able to deal with people who don't give full power.