So you're saying that you think the hamburger menus are just interim until the apps are properly rewritten, and then they'll disappear again? That doesn't sound very convincing to me.
Having said that, their removal from the Photos app does give me some small hope - perhaps they've realised how poor they are.
think of it like this:
> App gets developed as a universal app for desktop in the earliest previews of windows 10
> Down the road they start dropping them on the wp preview
> Since it's still a pre beta, what would you focus on first? changing the ui? or making the apps more optimized, which of those do you think negatively impacts the first impression of the OS, also, the UI is something they can throw on so quickly it doesn't really need attention so early
I'm not saying this is what happened, but considering how apps are slowly moving back to the pivot style, it's starting to seem more likely this is the case (also it makes perfect sense logically)
also, you cant talk as if this UI change for the photos app is something they just decided to do, they showed a mockup of how they wanted the photos app to look a LONG time ago... and it looked VERY similar to the new UI the photos app has..