I appreciate the effort this person put into the concept, and no doubt he's talented, but like many others, this guy misunderstands the purpose of the pivot and when it's appropriate.
In an
earlier post I described how the pivot is primarily intended for filtering/sorting purposes (like in the default e-mail app). Pivots were never intended for navigation between distinct/unrelated parts of an app. Microsoft states the exact same thing in their
developer guidelines
An app can easily have more than three or four distinct sections. The photo album app used in the concept has five, but apps can easily have double that amount. IMHO a pivot with five sections is already unpleasant to use. It necessitates an unacceptable amount of swiping. Worse, it's often not obvious which direction brings us to the desired section with the fewest number of swipes. Ultimately, a pivot works best with three sections. Four sections is still tolerable. Any more and the UX deteriorates exponentially. That's not adequate for use as a general purpose navigational mechanism.
The reason pivots are often misused as a navigational mechanism is because WP provides no suitable alternatives! The hub is the only exception, but that is only appropriate for media focused apps. For developers the pivot is a ready-made and simple choice, but when applied to navigational problems that's all it is. Simple for developers. It's not a good solution for users.
A better concept would completely divorce the concepts of filtering/sorting from navigation. Instead of trying to carry the missuses of the pivot over into W10M, it would be better to invent a wholly new and unrelated mechanism tailored specifically to navigation, while narrowing the pivots focus towards what it does best... filtering and sorting, like in the e-mail app, or as it is used in Tapatalk. Nothing more.