15 degrees nose up is about 3-5 degrees higher than I'd expect for a heavy -72; that would give you a decrease in speed for a start. This may be because the flight directors were being followed too slavishly (not looking through them) and making a height/speed trade.
Bearing in mind that after acceleration altitude you want to be increasing to white bug (7-8 degrees pitch attitude)then the attitude was definitely too great. When you then reached the inversion layer and the wind changed you were in an unfortunate flight attitude.