Honestly? I don't really know why anyone bothers to do launch events like this any more. Post a bunch of images, videos and some bullet points about the product somewhere. Done.
Well, the Sony PS4 event was actually fairly well done, especially in comparison. There was a lot of noise about them holding off on showing the actual box, but they talked extensively about games, about the things you could do with the console like screen sharing with friends, and about what the new hardware meant for developers and the kinds of doors it'd open for games.
It certainly wasn't without flaw, but it did get me somewhat excited about a console I didn't really have any interest in before the event.
Go back and re-watch the PS4 talk. It was mostly empty and mostly vapid. There were less details given than the Xbox presentation. They showed a controller and that vibrator-looking glowing thing you see in porn. The most interesting bit technology-wise was the old man head. I'll admit that was very cool but I wanted more info.
The screen streaming and sharing is a huge deal, IMO. The integration of the OnLive-like Gaikai service is also big. I just saw a lot more to be excited about.
And while they definitely spent time on the typical shooters and racers, they made a point of spending time on games more off the beaten path, as well.
What part of that did the Xbox miss? I only sporadically followed it, but it seemed to have plenty of detail on what you can do with it. Light on games perhaps, but it sounds like that's MS's direction with this generation.