Take a deep breath buddy.
Microsoft has no one to blame but themselves. Leaks are a nature of the beast, but people have had some of this information for a while now. If average joes on twitter can find this out by talking to the right people - this says more about the organization, how they plan their events, and their chain of trust than anything else.
I didn't leak any thing purposefully, and nor do I intend on doing so, but you have to respect and understand that an entire industry exists (games journalism cough) that works around the clock to get this sort of information.
Truthfully - as a gamer and an Xbox fan, you still haven't seen the meat and potatoes. What footage of the games have you seen outside of super compressed gifs and title cards? So take solice in that tomorrow your going to see a show filled games, hardware, and a new focus for a company. Don't worry about "suprises" stay their for the content. ^_^