I do not agree with a lot in this article, as it creates a superhuman impression of leaders. Leaders are everyday people who have challenges to overcome, if they do them successfully they are leaders.
Firstly, leaders and leadership needs to be defined. One can have many types of leaders. There is Thought leadership, Technical leadership, People leadership, Innovation leadership, etc. Often one type of leader can be poor or fail in other aspects of leadership. They often rely on a strength in a type of leadership to run a venture, project or organisation.
e.g. Steve Jobs was poor with people.
Secondly, I think leadership is more about determination to reach an objective and having ONE or MORE critical skills to achieve the objective. The rest is dealt with by a team (if required - often under different leadership). I never hear of people speaking about a team of leaders...
e.g. A father successfully steering his family through months of financial difficulty without a steady job can also be classed as successful leadership.
Thirdly, a leader needs experience in the field or challenge (if not he is less likely to succeed at crucial times).
Fourthly, any leader needs either a good supporting skill set , general knowledge or problem solving skills to" wing" a solution.
Finally, leaders and leadership cannot be place in a box - Leaders have succeeded with or without the criteria that you have mentioned.
Your article also mentions nothing about the leader's flexibility and adaptability. You also do not mention how a supportive teamwork under the leadership of another leader may enhance the leader's ability.
Many leaders have completely different skill set such as violence, manipulation and intimidation, also not mentioned. Are these still leaders, you decide...