In this great leadership speech by Jim Collins, he brings up his belief of the unimportance of personality. He believes that charisma is not necessarily a good thing. Instead, Collins feels that a leader who is an activist will be more effective at inspiring others.
Collins feels that too many leaders are in it for the wrong reasons and people can sense that. This will in turn have negative results despite whether or not those following the leader admit their feelings on the matter. Employees won't fully support a leader who has a large ego and doesn't have a good reason behind why they're doing what they do. A leader must channel their ego into their projects in order to inspire a following.