What about using kokyu-ho more fully as a starting point for learning both musubi and kazushi? It is a non-threatening (i.e. "safe") form of practice that allows students to experiment with what works and what doesn't. Maybe not enough time is being spent on these sorts of practice drills? Mobility training for kuzushi can come later; these "static" suwari waza and standing exercises are a good way for students to learn to physically and mentally listen and feel without any distractions. That's how you develop the skill to sense and changes and openings, or to know when to best create and seize advantage of them, IME.