It looks like the five finger pinch to get to running apps without double clicking the home button no longer works. I'm really missing this already. I wish they wouldn't do stuff like this.
It stops working for me on iPad Air from time to time, mostly when iPad was in sleep for some time.
You then need to disable an enable it again to get it back working.
I upgraded my iPad Mini Retina to iOS8 GM last week and the gestures stopped working for me several times since then. I've use the multitasking and return-home gestures for years with past iPads and only now having this issue so it's gotta have something to do with iOS8.