I think he gives Ive more power because of his experience with Paul Rand and the Nextstep logo.

http://www.youtube.com/watch?v=xb8idEf-Iak

In short Paul Rand tells Steve I will make you one design and I will solve your problem. Since then I believe he has given designers (Jon Ive in this case) their space to design whatever they want. Trust in the designer.