I don't think there is much debate about the role of Leadership. Leaders lead and by definition leaders take others on a journey towards a preferred destination.
Today I was reflecting on Andy Stanley's statement that it is okay for leaders to be uncertain. He points out that as a leaders we will be constantly dealing with uncertainty and if everything was certain we wouldn't need leaders. Instead of worrying and expending energy on the uncertainty of the day to day journey Andy wisely points out that leaders should instead focus their energy on being clear about the core vision or purpose and instilling a culture of flexibility in how it is realised. The role of the 'past' for a leader is therefore to clarify the vision as we celebrate how it has been realised and to be a foundation on which to continue to pursue the vision into the future.