Leadership development

The first step is to determine what you really want to develop - managers, executives or leaders.
Most so-called leadership development is actually executive development.
An executive occupies a multi-faceted, senior role with huge responsibilities.
Many of these responsibilities are managerial in nature - everything to do with getting the best possible return from all resources at the organization's disposal - money, people, material, energy and passion.
In some industries - those that compete on cost, for instance, the managerial functions of the executive's role are the main keys to competitive advantage.
In other industries - especially those that compete on innovation, more leadership is required.
However, in these cases, leadership need not come from executives. Some will, some might be shown by various other employees at all levels. See thought leadership for more on this.
An effective executive in this environment needs to be good at cultivating leadership in others and providing them with a supportive culture.
If you are signing up to a blanket leadership development process that pays no attention to the actual leadership versus managerial needs of your organization, then you are using a shot-gun approach.
If you are only developing leadership in senior executives or budding senior executives, then you might want to re-visit what leadership really means. See the pages on leadership in LeadersDirect for some ideas on this topic.