Wise words from the beard of Jim Dalrymple over at The Loop:
There are a few things you need to remember about iOS 7. First, it’s nowhere near finished in terms of design or functionality. Apple engineers stopped adding or changing the operating system before WWDC so they had a stable build to show during the keynote. It’s not done.
Second—and I’m surprised I even have to say this—it’s a beta for developers. This is not a build any individual user should install—ever. It wasn’t meant for you and installing it shouldn’t even be on your radar.