Here’s an article with an interesting question: will we ever get leadership development right? The article says let’s stop worrying about teaching leadership skills or competencies, and concentrate on teaching leadership “mind set”. This would include understanding the role of the leader, and the fact that leaders need to understand a variety of approaches that might be applied to any problem, depending upon the situation (in fact, we called this “situational leadership” back in the day).
It seems to me that both are required. If you’ve known me professionally for any length of time, you know that I’m big on building leadership competency models, with defining behaviors for each competency, before beginning development. Such a model represents a mutually-understood and agreed-upon “recipe for success” as a leader in a given organization. It will be unique to each organization, and will establish the 
framework within all leadership development is done.
Then it seems to me, as a separate agenda, we can talk separately about the role of the leader and situational leadership within that framework as well, along with other topics. Leadership skills, it seems to me, are just that: skills, which must be learned, like any other set of skills. There is still no substitute.