Kuzuha is the only Niji organ that can compete with Holo's 2 top dogs and he is basically the face of Niji at this point. So losing him, either through graduation or termination, will have a huge impact on Niji and Riku will do anything to satisfy him and make him stay for at least 2 more years, or find a new guy or girl who can achieve his success to keep the Niji train going and not have to rely on him