Well, it's already DP7 and the trackpad gestures still fail from time to time for me (see also http://forums.macrumors.com/showthread.php?t=1765701 for evidence in previous betas about this issue). It can very well happen for a subset of the gestures to stop working (e.g. swiping up/down with 4 fingers to bring up app expose/windows focus for selected app, although 4 finger swipe left/right works fine ...). GOOD NEWS: I accidentally found a solution for the unresponsive trackpad gestured while on DP6 (which also works in the 7th iteration) WITHOUT having to log out! All you need to do is to bring up the launchpad and pretend that you move one app over another one so as to create a folder. This magically unfreezes all the 'freezed' gestures on your trackpad. It's incredibly random, but it works like a charm .