One thing I would be interested in either from the OP or someone with experience with NVC, is how you recognize when you are being patronizing. Much of this communication style is the artifact of an implied power relationship, where the speaker already has the power, or is asserting power.
In negotiations, there is the idea of appealing to shared principles and interests, and NVC can be a way to depersonalize the issue to focus on that. But the example of handling, "No," with empathy is to directly personalize the issue and address feelings, vs. the negotiation view which would be to ask, "if no, given we agree on X, let's leave my perceived solution aside for a moment and find out how we get X."
I think empathy in business can often be zero sum, where it is just an expression of sympathy for someones lack of power in the situation, that is both psychologically horrible, and destroys value. I call that approach of fabricated empathy "seduce and smother," which is common in organizations today.
This article provides an essential and valuable tool. However, this difference between empathy and principle, is that an accurate interpretation of the distinction?