Personally I think team "consistent experience" won. They need WP10 to behave like Win10 so Windows users get a single UI language. The alternative is to bring pivots yo the desktop, but that might not work well. I do think pivots were awesome though.
The idea that WP10 must look like or behave exactly like W10 is incorrect. If Microsoft believes this themselves, then they have already failed, and it will fail in the market too. Ultimately, no matter how hard one tries, we can not provide the exact same UI experience on a 24" screen and a 4" screen without both being mediocre. With Windows 8.0 MS tried to bring a tablet-like UI to the desktop. We saw how poorly that worked out. If MS is hoping that the opposite approach will fair better, they are in for a disappointment. I'm sure they know better.
What MS needs are three things:
- A consistent UI design language specifically optimized for phones
- A consistent UI design language specifically optimized for tablets and larger screens
- A consistent mapping between the two
On a tablet, we will often have navigational controls that are always visible on the left or right side of the screen. On a smartphone, those navigational controls will be hidden in a side menu. That is an example of one such mapping. In Touch Office for tablets, most commands are displayed in a ribbon along the top of the screen. On a phone, those commands will apparently be hidden in the bottom app bar which needs to be opened to access them. That's another such mapping. My point is that MS is already fully aware that these "experiences" can't be identical. That's why such mappings already exist. That's why the notion that either WP had to lose the pivot control, or the pivot control had to be introduced to larger screens, is also incorrect. This requires just another mapping. I can think of a few ways a pivot control might be mapped to a larger screen. No big deal...
I don't know why MS decided to drop the pivot. I have a few hunches, but this "consistent experience" argument definitely isn't one of them. It also strikes me as somewhat ironic, considering how inconsistent the UI currently appears.