Your instincts are right. Disciplined planning is a necessary competency for project managers, but it's not at all sufficient to be an effective project Manager. Once the plan is defined, there are many other competencies required to ensure effective direction, control, communication and risk management of the project. My view from many years of experience is that the most important competencies of a PM are situational awareness, emotional intelligence and communications.
Good planning skills are certainly important, but as General George Patton is supposed to have said, "a good plan, aggressively executed now, is better that a perfect plan executed tomorrow.