Neither. What you need is a brand.
But since most people don't think of branding as a business tool, here is the logic in traditional business terms.
--With great leadership, the energy around the vision gets people excited. They want to follow the light. The leader is the light. You may not know exactly what things will look like once the vision is realized, but you want to be on the plane that takes you to that faraway place.
--With great management, the natural need of an employee for stability, predictability, order and fairness is supported. You wake up in the morning and you pretty much can plan your day. That's a nice feeling.
--Leaders tend to put their vision ahead of the people who work for them. This is the natural way of a leader. They are cognitively focused on the end state, not on what they think of as "handholding." This can be brutally painful for staff who want very much to be "managed in" to the vision.
--Managers tend to be unimaginative and uncaring about moving the needle. This is also natural. The job of a manager is to keep the trains running on time, not to build a new form of transportation. If the workplace is dominated by managers, employees lack inspiration.
The ideal state of course is one in which leaders and managers not only work together, but have a kind of mind meld about what kind of work they are doing and how it should be done. There is a clear distinction between the role of each, an appreciation for each, and an integration in the daily work flow that makes sense to employees.
A problem arises when leaders and managers are not working in sync, or worse than that, when there are contradictory visions of leadership within which the leader and the manager must operate. This is where the brand becomes extremely important, and communications as a subset of that.
The function of the brand is to organize the workforce around a shared set of principles -- yes, vision, mission and core values -- and to serve as a kind of law enforcement mechanism when those principles are broken.
The organization that looks at branding in a superficial way, like colors and logos and flashy billboards, is missing the point -- and thankfully those days are pretty much over.
But we have still not arrived at a place where branding is "operationalized" the way management consultants would have it done. Ideally the brand is the law of the land - the secular religion of the workplace. Everybody knows what it is, everybody knows what it means, and it takes very little to explain it to a newcomer.
Brands thrive on logic, clarity and simplicity. Therefore, they cannot work well when the workplace is organized around stopgaps, turf battles, or warring personalities.
Great leadership and great management are part and parcel of every brand. It is only the fool that focuses on technical prowess alone.
* All opinions my own.