What I keep thinking is, they probably should have sent Craig Federighi instead. Sure, he is not the CEO, but he has a lot of charisma. Tim isn't particularly bad at this, but he seems kind of tense when he's making his points. He isn't messing up anything, but it seems like he prepared for this word by word, which seems like he's lacking some passion.
To me it looks more like he is thoughtful and deliberate, not necessarily tense. He is like that in his interviews with Mossberg/Swisher as well.