I quiet like the description of the leadership definition especially as it un-focuses on personal leadership characteristics and looks at issues or matter that call for or create leadership. Leadership arises in all forms and shapes and may not have anything to do with organizations. I think of Ghandi, mother teresa, the founders of all hands and heart, the women/ men who lead by helping others, those who volunteer and create their own project, the young people who go on experiential learning expeditions to experiment with day leadership roles. Especially when working with these young people I see again and again that leadership many times is not related to personality but arises our if an issue the team is having. There could be a quiet and unassuming day leader in charge who would just ride along but an arising team issue sees this person rising to the occasion looking for collaborative and participate ways of resolving the issue so the team can move forward. 

The only addition I would made is that leadership calls for a vision which can be as simple as enabling people to communicate fearlessly in a team to building robots to clean up the world.