My guess is this is feature iPad 1 owners won't get. I don't see gestures on my iPad 1 but my buddy's iPad 2 has them enabled by default
iOS5 features page on apple.com
Side by side, near the bottom:
Multitasking Gestures for iPad
iOS 5 includes a few new moves and shortcuts to help you get around even quicker on your iPad: Using four or five fingers, swipe up to reveal the multitasking bar, pinch to return to the Home screen, and swipe left or right to switch between apps.
AirPlay Mirroring for iPad 2
Although the fact its off ipad1 at the moment does not bode well...
I hope it comes back in beta2