I have had the pleasure of seeing Alan Mulally give a couple of talks on leadership, and I can say that he is one of the most inspiring leaders I have ever seen (good video below of a talk he gave). Not because he drives people, but because he empowers them. Microsoft is a company with over 100,000 FTEs and honestly I don't think you need a great tech visionary leading as much as you need someone at the top to empower the tech visionaries running their products, and get out of their way.