When I tried the new phone app in Windows 10 I tried several times to slide the screen toward speed dial. I realized that this is not possible, it is not me, my hands are clean, it's them .
Also, 3rd party apps are greatly designed with pivot in mind. Do you imagine a Central Windows with hamburger menu? When it is so natural to just slide left or right for comments or more. (Oh, and I know an app like that, it is called "Windows Central ? The app!", and it is found in Android store)
Going to the hamburger menu is not fast, because you always have to pin point your finger to a very specific point at the screen. That's not fast. Especially when screen size is big.
What do you think all the existing store apps are going to show, that are coded for pivot and panorama controls? What does the Xbox music app in Win 10 show?